1990 C4 Corvette

1990 Corvette Overview

Although the C4 had already proven itself throughout the second half of the nineteen-eighties, there was no question that the Corvette would be transformed forever with the arrival of the 1990 model year.

In its entire history, there have been few model years that were so widely anticipated as the 1990 Corvette ZR-1.  Although the ZR-1 had originally been slated for a midyear-1989 release, it had been delayed until the 1990 model year because of engineering and design refinements that prevented it from being ready prior to 1990.

Now, as Chevrolet moved into a new decade, it did so with the most technologically advanced, and one of the most powerful Corvettes of all time.

Model: 1990 Corvette
Generation: C4 Corvette
Type: 2 Door Coupe, 2 Door Convertible
Available Colors: White, Steel Blue Metallic, Black, Turquoise Metallic, Competition Yellow, Dark Red Metallic, Quasar Blue Metallic, Bright Red, Polo Green Metallic, Charcoal Metallic
Engine: Base Model: 350CI 240/245 Horsepower, Tuned-Port Fuel Injected L98 V8 Engine. ZR-1: 350CI 375 Horsepower, LT5 V8 Engine
VIN: 1G1YY2380L5100001 – 1G1YY2380L5120597 (Corvette Coupe & Convertible)
1G1YZ23J6L5800001 – 1G1YZ23J6L5803049 (ZR-1 Corvette)
Transmission: 4-speed automatic (standard), 6 speed manual (optional)
Original Price: $31,979.00 (Coupe), $37,264.00 (Convertible)
Units Produced: 23,646
Specs: 1990 Corvette Spec List
1990 Corvette
The steering wheel of the 1990 Corvette (all variants) was modified to encase the SIR driver’s side air bag.

Although the automotive world was focused on the arrival of the ZR-1, all Corvettes built in 1990 received some minor improvements.  In an on-going effort to meet the first phase of the federal government’s “passive restraint” crash protection regulations, Chevrolet introduced a standard driver’s side airbag to its entire fleet, including the Corvette.

The supplemental inflatable restraint (SIR) airbag system was a first of its kind.  Additionally, the Corvette’s antilock braking system was upgraded with improved yaw control that allowed for more secure handling.

1990 Corvette interior
The newly designed 1990 Corvette interior included a revised instrument display and a completely re-designed driver and passenger side dashboard.

The L98 engine received a slight increase in power, boosting engine performance to 245 horsepower, thanks to the addition of an added air-intake speed density control system, a revised camshaft and an increased engine compression ratio.

A more efficient radiator was installed.  It worked so well that there was no longer a need for the optional boost fan (RPO B24) which had been offered from 1986 to 1989

The interior of the Corvette received some minor improvements as well.  A newly revised instrument display was introduced in the 1990 Corvette.  The new display now combined a digital speedometer with an analog tachometer, fuel gauge, oil pressure gauge, battery gauge, (and others).

An engine-oil monitor, which provided drivers with a display that calculated the useful oil life remaining and indicated when an oil change was necessary, was installed as part of the driver information center.

As CD technology was quickly replacing cassette tapes as the standard form of music media, Corvette offered a newly available Delco-Bose compact disc player audio system as an option in the 1990 model year.  When ordered, the CD player included a special lock-out feature to discourage theft; in the event that the stereo was removed from a car, it would require a special code to be entered to reactivate it or the stereo head unit would remain inoperative.

Also new was a glove box on the passenger side dashboard.  Lastly, the optional leather seats became available for all 1990 models.

1990 Corvette 245 HP
The 1990 Corvette 245 HP, L98 V-8 Engine.

Without question, the most significant change for 1990 was the introduction of an entirely new option (RPO ZR1) that would transform the Corvette line for all time.  While the ZR-1 was not a separate model in the Corvette line, its introduction represented a return to the glory days of the Corvette, when such engineering legends as Zora Arkus-Duntov and Bill Mitchell were building Corvettes that could be optioned out for their drivability and performance.

For many within General Motors, the ZR-1 literally marked a return to the days of “Detroit Muscle”, though this new Corvette would neither be built in Detroit (as all Corvettes since 1981 were built in Bowling Green, Kentucky) nor would it rely solely on sheer engine displacement to provide its unparalleled acceleration and drivability.

1990 ZR-1 Corvette

The ZR-1 was a costly option that would transform conventional Corvettes into a sports car that would truly rival the likes of Ferrari and Lamborghini.  Priced at $27,016 above the base model 1990 Corvette, the total sales price of the ZR-1 was a then-staggering $58,995, which, for its time, put the ZR-1 financially out of reach for many consumers – even those who had considered purchasing a base model Corvette.  Still, despite its costly price tag, it was still far more affordable than its Italian counterparts, making the ZR-1 a very desirable entry in the world of performance super cars.

At the time that the C4 had been introduced in 1984, it inherited an engine which was subpar to many of the engines that preceded it in earlier Corvettes.  The standard low-tech overhead-valve V8 engine was anything but impressive from a performance standpoint, and it had been outclassed by more powerful and better engineered engines of the European GT class vehicles of that same era.  Because of corporate policies and financial limitations, the design teams behind the Corvette – including Chief Engineer Fred Schaafsma and Corvette Engineering Chief Dave McLellan – were unable to truly grace the early C4’s with an engine that would properly serve to give Corvette its place in the venerable world of performance cars.

Lloyd Reuss, GM Vice President
Lloyd Reuss, former GM Vice President and General Manager of the CPC (Chevrolet-Pontiac-Canada) Group.

Still, General Motors’ people had begun considering the Corvette’s near future even before the first C4 had rolled off the production line.  Lloyd Reuss, who had spent much of his career working for General Motors as a powertrain engineer, would be promoted to General Motors Vice President in 1984 and would doubly serve as the general manager of the newly formed Chevrolet-Pontiac-Canada (CPC) group.

It was Reuss who insisted on keeping Chevy’s “halo vehicle” (as Reuss himself called the ZR-1 in its earliest days) as a top priority, despite corporate pressure to abandon the project.  He believed that the Japanese sports car lines would move in, take over, and eventually dominate the American sports car market if manufacturers like GM could not produce a vehicle that could more fully satiate the appetites of performance driven consumers.

Ironically, the staff behind the Corvette had long been exploring a number of ideas to increase the car’s performance numbers.  McLellan and Reuss turned to Powertrain Engineering Director Russ Gee to head up an endeavor to explore the development of new engine concepts to power the Corvette.  In turn, Gee assigned Roy Midgley, Chief Engineer of V-type Engines to the assignment and, working with Gee, the pair began to explore the options that were available to them.  Gee and MIdgley had solicited outside firms for engineering concepts that would help push the performance of small block engine performance well beyond the limitations of the day.

Out of the many conceptual ideas emerged an array of V6 and V8 engines, many of which included twin turbochargers, and a naturally aspirated V8 capable of producing up to 600 horsepower.  Ultimately, the turbo V6 was dismissed as running too harsh for conventional use in the Corvette.  Besides, it was long believed that no Corvette owner would ever be satisfied with a 6-cylinder Corvette, regardless of horsepower.  McLellan was interested by and supportive of the twin turbo V8 engine, but their fuel consumption and emissions were ultimately too high to be acceptable for use in a Corvette.

DID YOU KNOW: In the early development phases of the powertrain for the C4 Corvette, a number of turbocharged V6 and V8 engines were produced, including a twin-turbo V8 engine that gained considerable support amongst GM insiders. It was this early engine design, and a total of 14 prototypes that featured the twin turbo V8 engine, that led General Motors to ultimately “green-light” the Callaway Twin Turbo conversion option for the 1987 model year.

After extensive conceptual development, the realization was made that in order for Corvette, and moreover, a performance driven variant of the Corvette, to co-exist both as a true super car and as a conventional street car, it would have to include an engine and drivetrain that was considered “bi-modal”.  Effectively, this meant that the engine had to be quiet, docile, smooth, unobtrusive and undemanding in routine driving, yet be able to summon race-car speed and handling at a moment’s notice.

Tony Rudd, Lotus's Managing Director.
Tony Rudd, Lotus’s Managing Director.

To accomplish this, General Motors turned to England’s Group Lotus, a world renowned builder of championship Formula 1 cars and a leader in high-output engine technology.

As General Motors entered into negotiations to purchase Lotus in the spring of 1985, the Corvette Group met with Tony Rudd (Lotus’s Managing Director), to discuss adapting Lotus’s four-valve head technology to the Corvette’s 350-cubic inch V8 engine.

After extensive experimentation with the existing L98 V-8 engine, Rudd proposed building an all–new engine that would meet Chevrolet’s performance, emissions, and fuel-economy targets.  With continued prodding from Chevrolet’s engineering team, a lot of powerful support from Reuss and GM Board Chairman Roger Smith, and moreover, with Chevrolet’s acquisition of Lotus in 1986, GM management approved the development of a “brand-new no-holds-barred” V8 engine.

Of course, developing a high performance engine was not enough.  General Motors established specific guidelines that were to be strictly adhered to throughout the development of this new V8 engine.  First, the new engine was to provide acceleration that was second to none while simultaneously maintaining superior drivability at all speeds.  It had to have a fuel economy that was comparable to the existing L98 engine.  It had to be adaptable to the existing body/chassis structure of the current Corvette (meaning that no structural modifications were to be required for installation of the engine).

The desired power and torque gains of the new engine were to be at least 50% greater than the existing L98 and this increased power was to come from a modern engine having four valves per cylinder and twin overhead camshafts per cylinder bank.  A mandate was issued that the engine was to have electronically controlled ignition, fuel delivery and throttle actuation to ensure good drivability while maintaining an overall fuel economy of at least 22.5 miles per gallon and the ability to meet all U.S. emissions requirements.

Lastly, the new engine would have to have a pleasing underhood appearance, with no compromise in reliability or durability.

By the time the ZR-1 arrived in the automotive world, the rivalry between Corvette and Porsche had already been established. Even so, ZR-1’s arrival changed everything. Automotive reviewers like Car & Driver, Road & Track (and others) began performing comparisons of the ZR-1 Corvette and the Porsche 911. In almost all instances, it was universally agreed that the Corvette simply outperformed the Porsche 911. Further, the ZR-1 cost about half of the 911, making it the best “bang for the buck” between the two.

 

ZR-1 Corvette LT5 32 Valve Engine
The ZR-1 Corvette LT5 32 Valve Engine

Despite this long laundry list of specific requirements, the combined Lotus/Chevrolet-Pontiac-Canada engineering groups were up for the challenge.  Denoted “LT5”, this new power plant would become the latest in a long and sorted line of L-badged Corvette performance engines.

The LT5 was to be a 5.7 liter/350 cubic inch diameter 90-degree V8 engine with 4.4 inches between bore centers. Beyond its general similarities to the L98 engine in size and spec, the LT5 was unlike any other engine that had breathed life into a Corvette before it. An all-aluminum construction was deemed mandatory from the beginning of the LT5’s development because of aluminum’s ability to rapidly dissipate heat. Additionally, the use of aluminum would result in a much lighter engine than its cast-iron counterpart, which, when combined with its heat dissipating capabilities, would lead to increased operating efficiency and fuel economy.

Because of the location of the front frame rails on the existing C4 chassis, it was determined that the valve angle of the new engine would have to be 22 degrees to make the four-valve V8 as narrow as possible.  At its widest point, the new Corvette engine measured just 26.6 inches, which meant that the new engine would seat itself in the same engine bay space as the L98 had before it.

Exploded View of the LT5 Engine
Exploded View of the LT5 Engine

At its core, the engine utilized separate, “wet” cylinder liners, which were also constructed of aluminum.  These reduced bore by 0.1 inch compared to the L98 engine, thereby increasing stroke from 3.48 to 3.66 inches to maintain the 5.7-liter displacement.  The cylinder liners were specially matched to their bores, into which they locked via a simple slip-fit.

The interior surfaces were coated with Nikasil, a nickel-silicon alloy that provided an extremely durable but plaint surface for the specified lightweight cast-aluminum Mahle pistons.  The connecting rods and crankshaft were forged of steel to maximize their strength and durability.  To enhance the overall strength of the engine as a whole, the block was heavily ribbed and gusseted.  The usual five main crankshaft bearings were supported by a special one-piece aluminum cradle that attached to the block by no fewer than 28 bolts.  The bearings were oversized at 70 millimeters, which was considered necessary for reliable, sustained operation at 7,000 rpm.

Engine Cutaway Corvette
Engine Cutaway showcasing the Engine Induction and Fuel Injection Systems.

While the engine was fabricated to incorporate exacting standards and minimal tolerances between moving parts, a great deal of effort was also placed into ensuring proper lubrication within the engine.

The LT5 crankshaft was cross-drilled for internal centrifugal oiling from the front of the crank to the conrod pin bearings and main bearing journals.

The engine included a separate oil cooler with thermostatic control, and the crankcase consisted of a two-piece aluminum assembly with an integral pickup that assured proper feed and bottom-end oiling during hard cornering, (when sloshing oil might otherwise leave part of the oil sump momentarily dry.)

From an engineering standpoint, one of the most fascinating aspects of the LT5 engine is the unique three-stand engine induction system.  Much like the Tuned Port Injection that was used on the L98 engine since 1985, it took advantage of “Ram-effect” tuning.  A large, forward mounted air cleaner would feed a cast-aluminum throttle-body assembly with three throttle blades – a primary blade of 0.87-inch diameter and two larger, secondary blades measuring 2.32 inches across.  The throttle body, in turn, connected to an aluminum plenum chamber that branched into 16 individual runners, one for each intake port.  Eight of these would feed the primary ports and would operate continuously; the other eight had individual throttles for supplying the secondary ports under certain conditions. Each runner was given its own fuel injector that was supplied by twin tank-mounted electric fuel pumps and was activated in sequence by the engine control module (ECM).

The injection system of the LT5 actually operated in three, progressive stages.  In the “first stage” mode, air would be drawn into the throttle body and past the primary throttle blade to the plenum, from which it was distributed to the eight primary ports.  During this stage, the secondary throttle blades remained closed below 80 degrees (approximately) of the primary blade opening, which equated about 70 miles per hour on the road.  During the “second stage” mode, the secondary throttle blades would open to add air to the eight secondary runners and ports, providing that the ECM was satisfied that full power would be required.  In that event, the ECM would trigger the vacuum actuator to open the secondary runner throttles.  The third “mode” of the LT5 engine was commonly referred to as the “Valet Mode”.  Because the engine management system operated in stages that were mechanically controlled, the second stage performance could literally be locked out with a key.  The actuator could be manually disabled via a mechanism in the center console, engaging the “valet” mode, which inhibited full-power operation when handling the car over to parking-lot attendants or other vehicle operators who might otherwise not be trusted with the car.

>Like the 1989 L98 engine before it, the new LT5 engine was fitted with the new Multec (Multiple Technology) fuel injectors developed by General Motor’s Rochester Products division.  The new fuel injectors provided improved fuel atomizing and spray control.  They also claimed to require less operating voltage for improved cold-weather cranking performance and were less susceptible to clogging than earlier fuel injection designs.

LT5 Cutaway Drawing
LT5 Cutaway Drawing – Note the location of the four camshafts (two depicted on left engine cylinder bank.)

The LT5 came with a total of four camshafts, two per cylinder bank, one for each set of intake and exhaust valves.  Valves were actuated directly from the lobes on the cams, and the intake cams featured distinct primary and secondary lobe profiles to match the valve operation of the staged induction system.  Each bank’s pair of camshafts was driven by a steel duplex roller chain with a hydraulic tensioner.  An ECM-governed fuel shutoff limited the engine to a maximum rpm of 7,200 rpms

Engine valves were canted at 11 degrees to their respective ports in a classic cross-flow cylinder head.  Essentially a modified pentroof type, it allowed the spark plugs to be centrally placed for good flame propagation and thus faster, more complete combustion, for better efficiency and emission control.  With this combustion-chamber shape and slightly dished pistons, the engine’s compression ratio was a high 11.25:1.  Despite this, the fast burn design combined with the new injection system enabled the LT5 to run easily on regular (87 octane) unleaded fuel.

Although the plan had initially been to have Lotus design and GM construct it, it was determined by Manufacturing Manager Dick Donnelly that General Motor’s engine people were far too busy to take on such a complicated, small-volume project.  As with before, Russ Gee instructed Midgley to again seek outside help.  Although he reached out to a number of companies, including Lotus and another British firm known as Coventry Climax, none of these facilities offered the required production capabilities.

Ultimately, Chevrolet contracted with Mercury Marine, a company based out of Stillwater, Oklahoma that specialized in marine engines, to build the LT5 engine for the ZR1.  They were also contracted to develop a marine version of the new powerplant, which was fitting as many of Mercury Marine’s “Mercruiser” engines had originated as GM designs.  Given the anticipated low production numbers that were anticipated for the ZR-1, it was reasonable to assume that Mercury Marine would have no issues keeping up with the demand for these specialized, high performance engines.    Interestingly, whenever an LT5 engine required any major mechanical service, A Chevy Dealer’s service department would have to remove the engine and ship it back to Mercury Marine.  Once that happened, the car’s owner would have one of two possible choices:  They could either receive an entirely new engine or they could get the original engine repaired. This practice would continue through the end of calendar-year 1993, at which point Chevrolet assumed all service responsibilities for the powerplant.

Upon the completion of the engine’s fabrication and assembly in Stillwater, they would be loaded on a flatbed and shipped to the Corvette Assembly Plant in Bowling Green, Kentucky.  The LT5 engine weighed in at only 39 pounds more than the L98, which was amazing since it produced a noted 60 percent increase in horsepower over the base model Corvette.  These new engines would turn even the largest cynics into believers.  Yes, despite its near-staggering performance numbers, the LT5 maintained a respectable fuel economy – approximately 22 miles per gallon city/highway.

The engine was mated to the rear axles and, in turn, the rear wheels by a brand new six-speed transmission.  The transmission was developed by General Motors and a renowned German transmission company called Zahnradfabrik Friedrichshafen AG – better known simply as ZF.  As all ZR-1 Corvettes were to include six-speed manual transmissions, this new transmission was a vast improvement over the inefficient (and often clunky) 4+3 Overdrive manual transmission that preceded it.

In both the standard Corvette and the ZR-1 variant, the ZF gearbox offered two important new features over the previous Corvette transmission.  First, its gears were arranged to minimize synchronizer loads.  Second was the inclusion of Computer-Aided Gear Selection (CAGS) which was included to help improve fuel economy.  The CAGS system was not solely intended for the Corvette, but was also used on Chevrolet Camaros and Pontiac Firebirds that were equipped with a six speed manual transmission.

The CAGS system utilized an integral-rail shift linkage with a solenoid actuator that guided the lever from first gear directly to fourth whenever the car was running at 12-19 miles per hour with at least a partly warm engine and a throttle opening of no more than a third.  While the CAGS system did tend to restrict drivability of the car by limiting the driver’s ability to manually shift the transmission at their discretion, it also helped to prevent the ZR-1 from falling prey to the gas-guzzler tax.

Regardless of drivers’ varying opinions of the CAGS system, there was no question whatsoever that the new ZF gearbox was a major improvement over the clunky, awkward 4+3 manual transmission that preceded it.

1990 ZR-1 Rear
The ZR-1’s rear fenders were pushed out three inches to accommodate its larger rear tires.

Early “complete car” testing, both in England and America, involved the installation of the brand new LT5 engines in stock-bodied Corvettes.  From the onset however, Reuss and McLellan knew that a new look would be required to differentiate the ZR-1 from the base model Corvette.  For Reuss, it was important that the “King of the Hill” stand out from the crowd even more than a typical Corvette.

McLellan’s motivation involved fewer form considerations but an increased focus on functionality. Ultimately, the ZR-1 Corvette featured a variety of subtle, but notable changes to the base model Corvette.  The car’s rear fenders were pushed out three inches wider than those on the L98 models. The sole reason for this modification was to a accommodate the ZR-1’s massive 315/35ZR17 rear tires.  These tires, which measured 11 inches wide, added 1.5 inches of surface contact/traction when compared to the standard-issue 275/40ZR17’s (which were still on the front axles, as on L98 models.)

1990 ZR-1 and L98 Corvette
1990 ZR-1 and L98 Corvette. Note the differences between the rear fascia and taillights.

Aside from the rear fenders, the only notable cosmetic change to the car was the introduction of a new rear bumper.  Where the base model Corvette featured a concave bumper with round taillights, the ZR-1’s rear bumper was three inches wider, convex in shape and included squared off taillights. Corvette engineers claimed that the convex rear end would provide greater aerodynamics to the car (it would become standard on all 1991 (and later models) C4 Corvettes.)  Additionally, a ZR-1 badge was added to the rear bumper (mounted to the far right just below the perimeter rub strip).  Lastly, a high mount taillight was installed above the rear windshield which would remain a unique identifier of the ZR-1 line until the car’s retirement in 1995.  Despite the dramatic and extreme upgrades that were made to the mechanical systems of the ZR-1, this upgraded Corvette was scarcely discernible to the casual observer.

ZR-1 emblem
The ZR-1 emblem and squared off taillights were some of the only distinguishing differences between the L98 and ZR-1 models.

While the engine and transmission upgrades were the most notable of the mechanical upgrades, other modifications that were part of the ZR-1 package included a heftier differential, 13-inch twin caliper front disc brakes (which had been previously introduced on the 1988 Z51 package), and a reinforced front-end structure designed to help with counter cowl shake on rough roads.  The race-oriented Z51 handling package was also included as part of the ZR-1 option as was the Selective Ride Control suspension option that was added elsewhere in the line as optional equipment for 1989.

As was expected, motoring and automotive journalists were quick to praise the ZR-1’s increased muscle, and their reviews featured performance figures that were unparalleled with anything else in its class.  The top reviewers recorded unprecedented 0-60mph times ranging from 4.5 to 4.9 seconds, racing though the quarter mile in just 12.8 seconds at a speed of 111 mph.  Testers reached top speeds as high as 175 miles per hour.
Not only was the ZR-1 eagerly anticipated, it created an instant sensation in the marketplace.  Even before the ZR-1 was officially made available, Corvette enthusiasts were clamoring for the opportunity to own Chevrolet’s latest and possibly greatest Corvette ever.  A total of 3,049 fanatics paid well in excess of the already incredibly expensive suggested retail price for the chance to be the first to own one of the fastest cars in the world.   It has been reported that some dealers initially asked for – and received –as much as $100,000 for the first commercially available ZR-1s.

While reviewers praised the car for its uncompromising acceleration, the ZR-1 was also criticized for its high sticker price, its unpopular CAGS skip-shift feature, and most especially its general lack of unique body styling.  With the exception of the aforementioned items, the physical appearance of a ZR-1 and a standard L98 Corvette were virtually indistinguishable to the causal observer, and critics noted that individuals who were going to spend the additional twenty-seven thousand (or more) dollars for a unique, one-of-a-kind sports car should receive just that.

Still, despite its commonplace appearance, the ZR-1 was anything but commonplace when it came to breaking performance records.  In March, 1990, a stock ZR-1 would set 12 FIA (Fédération Internationale de l’Automobile) world records for speed and endurance at the Firestone’s 7.7 Mile Test Track in Stockton, Texas.  Three of these records were set regardless of classifications – which was the first time in 50 years that they had been claimed by a regular production car.  The ZR-1’s level of performance was so advanced for its time that no competitor would touch its records until 2001 when a specially built, 600 horsepower, Volkswagen prototype known as the “W-12” would go on to surpass it.

A 1990 SCCA World Challenge Racing Corvette.
A 1990 SCCA World Challenge Racing Corvette.

With the ZR-1 now commercially available, the Callaway twin-turbo Corvette would quickly fall out of favor with consumers everywhere.  In 1990, the Callaway Corvette sold just 58 units, compared to the 3,049 ZR-1 equipped models which were sold – most to buyers who had been put on a waiting list until its official introduction.  Twenty-three Corvettes were built with heavy-duty suspensions for use in the 1990 new World Challenge racing serie and could readily be ordered via regular dealer channels.  Buyers could choose a Chevy engine or they could provide their own engines.  In either case, any modifications from the factory engine were the responsibility of the owners/racers.

Overall, sales of the Chevy Corvette dropped slightly in 1990, with a total sales of 23,646 units.  Despite this decrease in sales, there was no question that Corvette had achieved an incredible success with the introduction of the ZR-1.Without question, “the King” had arrived.

See full 1990 C4 Corvette Image Gallery

1990 Corvette Specifications

1990 Corvette Main Specs

MODEL: 1990 Chevrolet Corvette
BODY STYLE: Two-door Coupe/Hatchback, front engine, rear wheel drive
MANUFACTURING LOCATION: Bowling Green, Kentucky
CONSTRUCTION: Fiberglass body, unibody construction with partial, front frame including both steel and stainless steel components.
VEHICLE NUMBERS (VIN): 1G1YY2380L5100001 THRU 1G1YY2380L5120597
1G1YZ23J6L5800001 THRU 1G1YZ23J6L5803049 (ZR-1)
VIN SUFFIX: ZSA: 350 CUBIC INCH, 245/250 HP, AUTOMATIC TRANS
ZSB: 350 CUBIC INCH, 245/250 HP, MANUAL TRANS. OIL COOLER
ZSC: 350 CUBIC INCH, 245/250 HP, AUTO TRANS, OIL COOLER
ZSD: 350 CUBIC INCH, 375 HP, AIR CONDITIONING
ZSH: 350 CUBIC INCH, 375 HOP ELECTRONIC AIR CON CONTROL
ENGINE BLOCK NUMBER: 10090511: 350 CUBIC INCH, 375 HORSEPOWER
14093638: 350 CUBIC INCH, 245/250 HORSEPOWER
HEAD NUMBER: 10088113: 350 CUBIC INCH, 245/250 HORSEPOWER
10106178: 350 CUBIC INCH, 375 HORSEPOWER (RIGHT HAND)
10106179: 350 CUBIC INCH, 375 HORSEPOWER (LEFT HAND)
Note: For Callaway Twin-Turbo, Chevrolet engine coding was replaced as follows: First two digits for year, next three digits for Callaway sequence, last four digits to match the last four digits of the vehicle identification number.

1990 Corvette Pricing & Options

CODE: DESCRIPTION: QUANTITY: RETAIL PRICE:
1YY07
Base Corvette Sport Coupe
16,016
$31,979.00
1YY67
Base Corvette Convertible
7,630
$37,264.00
AC1
Power Passenger Seat
20,419
$270.00
AC3
Power Driver Seat
23,109
$270.00
AQ9
Sport Seats, leather
11,457 $1,050.00
AR9
Base Seats, leather
11,649
$425.00
B2K
Callaway Twin Turbo (not GM installed)
58
$26,895.00
CC2
Auxiliary Hardtop (convertible)
2,371
$1,995.00
C2L
Dual Removable Roof Panels (coupe)
6,422  $915.00
24S
Removable Roof Panel, blue tint (coupe)
 7,852
$615.00
 64S Removable Roof Panel, bronze tint (coupe)  4,340
$615.00
C68
Electronic Air Conditioning Control
22,497
$180.00
FX3
Selective Ride and Handling, electronic
7,576
$1,695.00
G92
Performance Axle Ratio
9,362
$22.00
K05
Engine Block Heater
1,585
$20.00
KC4
Engine Oil Cooler
16,221
$110.00
MN6
6-Speed Manual Transmission
8,101
$0.00
NN5
California Emission Requirements
4,035
$100.00
UJ6
Low Tire Pressure Warning Indicator
8,432
$325.00
UU8
Stereo System, Delco-Bose
6,701
$823.00
U1F
Stereo System With CD, Delco-Bose
 15,716  $1,219.00
 V56  Luggage Rack (convertible)  1,284
$140.00
 Z51  Adjustable Handling Package (coupe)  5,446
$460.00
ZR1
Special Performance Package  (coupe)
3,049
$27,016.00

1990 Corvette

1990 Corvette Exterior & Interior Colors

Color Options

CODE EXTERIOR TOTAL SOFT TOP INTERIOR COLOR OPTIONS
10 White 4,872
Black, Saddle, White
Blue, Black, Grey, Red, Saddle
25
Steel Blue Metallic
813
Black, White
Blue, Black
41 Black 4,759
Black, White
Blue, Black, Grey, Saddle
42
Turquoise Metallic
589
Black, Saddle
Black, Saddle
53
Competition Yellow
278
Black, Saddle, White
Black, Grey, Saddle
68
Dark Red Metallic
2,353
Black, Saddle, White
Black, Saddle
80
Quasar Blue Metallic
474
Black, Saddle
Black, Saddle
81
Bright Red
6,956
Black, Saddle, White
Black, Grey, Red, Saddle
91
Polo Green Metallic
1,674
Black, Saddle
Black, Saddle
96
Charcoal Metallic
878
Black, Saddle
Black, Grey

Exterior Colors

1990 Corvette Colors

Interior Colors

1990 Corvette Colors interior

1990 Corvette

1990 Corvette Powertrain Specifications

Engine (Coupe/Convertible)

Engine: L98 5.7 OHV 350 V-8. Tuned-Port Fuel Injection (COUPE)
Cylinders: V8
Block Material:
Cast Iron Alloy
Displacement: 5.7 Litre/350 Cubic Inches
Bore & Stroke: 4.00 x 3.48 inches
Valvetrain: OHV, 2 valves per cyl.
Cylinder Head Material: Aluminum
Cylinder Block Deck Height: 9.025 Inches
Compression Ratio: 9.50:1
Horsepower: 250 HP @ 4,400 RPM
Torque: 350 lb-ft @ 3,200 rpm
Fuel Delivery: Multi-Port Fuel Injection
Fuel Capacity: 20.0 Gallons
Oil Capacity: 4.5 Quarts (Without Filter)
Total Dressed Engine Weight (Dry): 585.7lbs
Transmission: 4 Speed Auto Transmission (Standard), 6 Speed Manual Transmission (Optional)
Standard Axle Ratio: 2.59:1 (Automatic), 3.33:1 (Manual)

Engine (ZR-1)

Engine: LT5 5.7 OHV 350 V-8. Multi-Port Fuel Injection (COUPE)
Cylinders: V8
Block Material:
Aluminum*
Displacement: 5.7 Litre/350 Cubic Inches
Bore & Stroke: 3.90 x 3.66 inches
Valvetrain: OHV, 2 valves per cyl.
Cylinder Head Material: Aluminum
Cylinder Block Deck Height: 9.025 Inches
Compression Ratio: 11.0:1
Horsepower: 375 HP @ 6,000 RPM
Torque: 370 lb-ft @ 4,800 rpm
Fuel Delivery: Tuned-Port Fuel Injection
Fuel Capacity: 20.0 Gallons
Oil Capacity: 9.6 Quarts (Without Filter)
Total Dressed Engine Weight (Dry): 596.0 lbs
Transmission: 4 Speed Auto Transmission (Standard), 6 Speed Manual Transmission (Optional)
Standard Axle Ratio: 2.59:1 (Automatic), 3.33:1 (Manual)

*The engine crankcase, cylinder case, cylinder heads is aluminum with cast-in nodular cast iron bearing inserts.

Transmission

6 SPEED MANUAL GEAR RATIOS  4 SPEED AUTOMATIC GEAR RATIOS
1st GEAR: 2.68:1 1st GEAR: 3.06:1
2nd GEAR: 1.80:1 2nd GEAR: 1.63:1
3rd GEAR: 1.31:1 3rd GEAR: 1.00:1
4th GEAR: 1.00:1 4th GEAR: 0.70:1
5th GEAR: 0.75:1 REVERSE: 2.29:1
6th GEAR: 0.50:1
REVERSE: 2.50:1

1990 Corvette Wheels, Suspension & Brakes

Suspension (Coupe/Convertible)

Front Suspension Single fiberglass composite monoleaf transverse spring with unequal-length aluminum control arms and stabilizer bar.
Rear Suspension Fully independent five-link system with transverse fiberglass single-leaf springs, aluminum upper/lower trailing links and strut-rod tie-rod assembly.

Suspension (ZR-1)

Front Suspension Single fiberglass composite monoleaf transverse spring with unequal-length aluminum control arms and stabilizer bar.
Rear Suspension Fully independent five-link system with transverse fiberglass single-leaf springs, aluminum upper/lower trailing links and strut-rod tie-rod assembly.

Wheels & Tires (Coupe/Convertible)

Front Tires Goodyear Eagle ZR, P275/40ZR-17
Rear Tires Goodyear Eagle ZR, P275/40ZR-17
Front Wheels 17 x 9.5 Inches, 5 Bolt Cast Alloy
Front Wheels 17 x 9.5 Inches, 5 Bolt Cast Alloy

Wheels & Tires (ZR-1)

Front Tires Goodyear Eagle ZR, P275/40ZR-17
Rear Tires Goodyear Eagle ZR, P315/35ZR-17 ZR-1
Front Wheels 17 x 9.5 Inches, 5 Bolt Cast Alloy
Front Wheels 17 x 11 Inches, 5 Bolt Cast Alloy

Brakes (Coupe/Convertible)

Type ABS Power-Assist Vented Brakes
Front Brakes 12.0 Inches (13.0 Inches – RPO Z51)
Rear Brakes 12.0 Inches (13.0 Inches – RPO Z51)

Brakes (Coupe/Convertible)

Type ABS Power-Assist Vented Brakes
Front Brakes 12.0 Inches (13.0 Inches – RPO Z51)
Rear Brakes 12.0 Inches (13.0 Inches – RPO Z51)

1990 Corvette

1990 Corvette Exterior Dimensions

Coupe Dimensions

1990 Corvette Dimensions

Exterior Dimensions

Exterior Dimensions
Model L98 Coupe L98 Convertible ZR-1 Coupe
Wheelbase 96.2 Inches 96.2 Inches 96.2 Inches
Overall Length 176.5 Inches 176.5 Inches 177.4 Inches
Total Body Width 71.0 Inches 71.0 Inches 74.0 Inches
Overall Height 46.7 Inches 46.7 Inches 46.8 Inches
Front Track Width 59.6 Inches 59.6 Inches 59.6 Inches
Rear Track Width 60.4 Inches 60.4 Inches 61.9 Inches

Interior Dimensions

Interior Dimensions
Model L98 Coupe L98 Convertible ZR-1 Coupe
Headroom 36.4 Inches 36.5 Inches 36.4 Inches
Shoulder Room 54.1 Inches 54.1 Inches 54.0 Inches
Hip Room 49.3 Inches 49.3 Inches 49.3 Inches
Leg Room 42.6 Inches 42.6 Inches 42.6 Inches

Capacities

Capacities
Model L98 Coupe L98 Convertible ZR-1 Coupe
Passenger Capacity 2 – Driver & Passenger 2 – Driver & Passenger 2 – Driver & Passenger
Curb Weight – Automatic (LBS) 3,284 N/A N/A
Curb Weight – Manual (LBS) 3,330 3,336 3,465
Cargo Volume (CU.FT) 17.9 Cubic Feet 17.9 Cubic Feet 12.6 Cubic Feet
Fuel Capacity (GALLONS/LITERS) 20.0/76.0 20.0/76.0 20.0/76.0
Engine Oil Capacity (QTS./LITERS) 4.5 4.5 8.0
Coolant Capacity (QTS./LITERS) 14.6 14.6 14.6
Coefficient of Drag 0.33 N/A N/A
Weight Dist. Front/Rear (%) 50/50 50/50 50/50

1990 Corvette

1990 Corvette Performance Results

Model:
L98 Coupe
L98 Convertible
ZR-1 Coupe Callaway
0-30 MPH:
0-60 MPH:
0-100 MPH:
QUARTER MILE:
QUARTER MILE SPEEDS:
TOP SPEED:
2.1(A)/2.2(M)
5.7(A)/5.6(M)
N/A
14.2(A)/14.1(M)
99.1(A)/101.5(A)
N/A
2.4 Seconds
6.3 Seconds
N/A
14.8 Seconds
95.0
N/A
N/A
4.9 Seconds
11.5 Seconds
13.4 Seconds
108.5
N/A
2.1 Seconds
5.1 Seconds
10.58 Seconds
13.11 Seconds
112.0
172

1990 Corvette

1990 Corvette Vehicle Identification Numbers (VIN)

VIN Range 1G1YY2380L5100001 – 1G1YY2380L5120597 (Corvette Coupe & Convertible)
1G1YZ23J6L5800001 – 1G1YZ23J6L5803049 (ZR-1 Corvette)
1 (First Digit) 1 – United States
G (Second Digit) Manufacturer.  G – General Motors
1 (Third Digit) Manufacturer Division. 1 – Chevrolet
YY/YZ(ZR-1) Make of Car. YY – Corvette  Coupe/Convertible.  YZ – ZR-1 Corvette (Coupe Only)
2/3 (Sixth Digit) 2 – Two Door Hatchback Coupe, 3 – Two Door Convertible
3 (Seventh Digit) Type of Restraint System.  3 – Passive Restraint System.
8/J (ZR-1) Type of Engine. 8 – L98: 5.7 Liter, 350CI Engine with Tuned-Port Injection. J – LT5: 5.7 Liter, 350CI, 32 Valve Engine with Tuned-Port Injection
0/6 (ZR-1) Check Digit.
L (Tenth Digit) The Model Year. J – 1990
5 (Eleventh Digit) Location of the Assembly Plant. 5 – Bowling Green, Kentucky
1XXXXX (Twelfth thru Seventeenth Digits) Production Sequence Numbers.

The last six digits begin at 100001 and run thru 120597, accounting for each of the 20,597 Corvette Coupes/Convertibles built in 1990. Additionally, the last six digits of the ZR-1 VIN begin at 800001 and run thru 803049, accounting for each of the 3,049 ZR-1 Corvette Coupes built in 1990. Each Vehicle Identification Number (VIN) is unique to an individual car.

For all 1990 Corvettes, the Vehicle Identification Number was stamped on a plate on the inner vertical surface of the left windshield pillar visible through the windshield.

Used to calculate the characters in the serial number and gives it a single digit code that can be used to verify the serial number is legitimate. (Note: The Check digit number varies depending on each specific VIN number.)

1990 Corvette

1990 Corvette Factory Options

CODE: DESCRIPTION: QUANTITY: RETAIL PRICE:
1YY07
Base Corvette Sport Coupe
16,016
$31,979.00
1YY67
Base Corvette Convertible
7,630
$37,264.00
AC1
Power Passenger Seat
20,419
$270.00
AC3
Power Driver Seat
23,109
$270.00
AQ9
Sport Seats, leather
11,457 $1,050.00
AR9
Base Seats, leather
11,649
$425.00
B2K
Callaway Twin Turbo (not GM installed)
58
$26,895.00
CC2
Auxiliary Hardtop (convertible)
2,371
$1,995.00
C2L
Dual Removable Roof Panels (coupe)
6,422  $915.00
24S
Removable Roof Panel, blue tint (coupe)
 7,852
$615.00
 64S  Removable Roof Panel, bronze tint (coupe)  4,340
$615.00
C68
Electronic Air Conditioning Control
22,497
$180.00
FX3
Selective Ride and Handling, electronic
7,576
$1,695.00
G92
Performance Axle Ratio
9,362
$22.00
K05
Engine Block Heater
1,585
$20.00
KC4
Engine Oil Cooler
16,221
$110.00
MN6
6-Speed Manual Transmission
8,101
$0.00
NN5
California Emission Requirements
4,035
$100.00
UJ6
Low Tire Pressure Warning Indicator
8,432
$325.00
UU8
Stereo System, Delco-Bose
6,701
$823.00
U1F
Stereo System With CD, Delco-Bose
 15,716  $1,219.00
 V56  Luggage Rack (convertible)  1,284
$140.00
 Z51  Adjustable Handling Package (coupe)  5,446
$460.00
ZR1
Special Performance Package  (coupe)
3,049
$27,016.00

Base Corvette Sport Coupe (1YY07)

  • The base price of the 1990 Chevrolet Corvette Coupe without any optional equipment.
  • A 350 cubic inch, 245/250 horsepower engine, 4-speed automatic transmission, removable body-color roof panel, and cloth seats were included in the base price.
  • Seat designs were the same for 1990 as they had been for previous years with the exception that backs would latch in the forward position. Sports seats were available with all models and suspensions in 1990.
  • An air intake speed density control system, camshaft revision, and compression ratio increase added 5 horsepower to base-engines, increasing base horsepower from 240hp to 245hp (except coupes equipped with 3.07:1 or 3.33:1 axle ratios which increased horsepower from 245hp to 250hp because of their less restrictive exhaust systems.
  • The 1990 model instrument display panel was redesigned as a “hybrid” combining a digital speedometer (similar to that found on earlier model C4’s) and conventional analog gauges for the rest of the display – including the tachometer, oil pressure, battery voltage and fuel levels.
  • An engine oil life monitor calculated useful oil life based on engine temperature and revolutions. An instrument panel display alerted the driver when an oil change was recommended.
  • A supplemental inflatable restraint system (SIR) with airbag was added to the driver’s side of the dashboard and a glove box was added to the passenger side (a feature previously absent on all earlier model C4’s).
  • The “ABS Active” light was removed from the driver information center.

Base Corvette Convertible (1YY67)

  • The base price of the 1990 Chevrolet Corvette Convertible without any optional equipment.
  • A 350 cubic inch, 245/250 horsepower engine, 4-speed automatic transmission, removable body-color roof panel, and cloth seats were included in the base price.
  • Seat designs were the same for 1990 as they had been for previous years with the exception that backs would latch in the forward position. Sports seats were available with all models and suspensions in 1990.
  • An air intake speed density control system, camshaft revision, and compression ratio increase added 5 horsepower to base-engines, increasing base horsepower from 240hp to 245hp (except coupes equipped with 3.07:1 or 3.33:1 axle ratios which increased horsepower from 245hp to 250hp because of their less restrictive exhaust systems.
  • The 1990 model instrument display panel was redesigned as a “hybrid” combining a digital speedometer (similar to that found on earlier model C4’s) and conventional analog gauges for the rest of the display – including the tachometer, oil pressure, battery voltage and fuel levels.
  • An engine oil life monitor calculated useful oil life based on engine temperature and revolutions. An instrument panel display alerted the driver when an oil change was recommended.
  • A supplemental inflatable restraint system (SIR) with airbag was added to the driver’s side of the dashboard and a glove box was added to the passenger side (a feature previously absent on all earlier model C4’s).
  • The “ABS Active” light was removed from the driver information center.

Power Passenger Seat (AC1)

  • Optional, six-way, adjustable passenger seat.
  • This option was included as part of the ZR1 package.

Power Driver Seat (AC3)

  • Optional, six-way, adjustable driver seat.
  • This option was included as part of the ZR1 package.

Sports Seat, Leather (AQ9)

  • Special sport seats that featured inflatable lumbar support and power-adjusted side bolsters
  • This option was included as part of the ZR1 package.
  • Seat designs were the same for 1990 as the previous year except that the seats would latch in the forward position.
  • Sports seats were available with all models and suspensions in 1990.
  • Base Seats, Leather (AR9)
  • Leather cover option for the standard, base driver and passenger seats.
  • Seat designs were the same for 1990 as the previous year except that the seats would latch in the forward position.

Callaway Twin Turbo (not GM installed) (B2K)

  • Addition of Callaway Twin Turbos to the existing L98 engine.
  • This option generated a specific equipment build with standard engines at the Corvette assembly plant. The cars were then drop-shipped to Callaway’s Connecticut shop for installation of Callaway-modified twin-turbo engines.
  • This is not a factory installed option. The Callaway Corvette could be ordered through participating Chevrolet dealers. Fully assembled Corvettes were then shipped from the Bowling Green Corvette plant to
  • Callaway Engineering in Old Lyme, Connecticut, where it received engine (and other) modifications.
  • The 1990 Callaway Corvette had performance ratings of 390 horsepower and 562 lb.-ft torque.
  • Automatic transmissions (reworked truck Turbo Hydramatic 400s) were available for $6500.00
  • Full Chevrolet warranty applied except for powertrain which was covered by Callaway for twelve months or 12,000 miles.

Auxiliary Hardtop (convertible) (CC2)

  • An optional, removable hardtop.
  • This option was new for the 1990 Corvette Convertible.

Dual Removable Roof Panels (coupe) (C2L)

  • Included both a tinted, transparent glass top and a painted top.

Removable Roof Panels, blue tint (coupe) (24S)

  • Blue tinted removable glass top.

Removable Roof Panels, bronze tint (coupe) (64S)

  • Bronze tinted removable glass top.

Electronic Air Conditioning Control (C68)

  • Air conditioning system electronic control unit.

Selective Ride & Handling, Electronic (FX3)

  • Electronically controlled suspension with manual ride selection.
  • FX3 provided three variations of suspension control regulated by a console switch.
  • This option was included as part of the ZR1 package.

Performance Axle Ratio (G92)

  • Optional performance axle ratio of 3.07:1 or 3.33:1.
  • Was only offered when the Corvette was ordered with an automatic transmission.
  • The actual “Performance Axle Ratio” varied from year to year. The G92 Option was available when ordering either the Corvette or the Camaro throughout the 1980’s and early ’90’s.

Engine Block Heater (K05)

  • An electric heater that heats the engine of a car to ease starting in cold weather.
  • This option was not available with the ZR1 option.

Engine Oil Cooler (KC4)

  • Internal cooler used to cool internal components of the automobile’s internal combustion engine.

6-Speed Manual Transmission (MN6)

  • An optional, no-cost, 6-speed manual transmission.
  • The six-speed manual transmission was designed jointly by ZF (Zahnradfabrik Friedrichshafen) and Chevrolet and was initially built by ZF in Germany.
  • A computer-aided gear selection feature bypassed second and third gears (and locked out fifth and sixth) for improved fuel economy when a series of low performance criteria were met.

California Emission Requirements (NN5)

  • Revised emission/exhaust components to meet California Emission standards

Low Tire Pressure Warning Indicator (UJ6)

  • Low tire/air pressure monitoring and warning system.
  • Sensors strapped to each side of the inside of each wheel sent a radio signal to a instrument-panel receiver if pressure in any tire dropped below a preset limit.
  • This option was included as part of the ZR1 package.

Stereo System, Delco-Bose (UU8)

  • 200 watt Delco Bose AM/FM stereo radio with cassette.

Stereo System with CD, Delco-Bose (U1F)

  • 200 watt Delco Bose AM/FM stereo radio with compact disc player.
  • This option was included as part of the ZR1 package.
  • To discourage theft, the CD player required an electronic security code input after battery disconnect.

Luggage Rack (convertible) (V56)

  • Optional luggage rack that was mounted to the rear decklid of the Corvette convertible.

Performance Handling Package (coupe) (Z51)

  • Heavy Duty Steering and Suspension Upgrade for improved handling.
  • The Z51 option included RPO KC4 Engine Oil Cooler, heavy duty suspension and brakes.
  • Was only available in coupes equipped with a manual transmission.

Special Performance Package (coupe) (ZR1)

  • Extensive performance upgrades to the base model Corvette.
  • The ZR1 option included unique bodywork (doors, rear quarters, rocker panels, rear fascia, and rear upper panel.
  • ZR1 optioned Corvettes were fitted with special Goodyear Z-rated P315/35ZR17 tires that were mated to 11-inch wide rear rims.
  • The ZR1 option included a number of other RPO’s (normally listed separately) including: Power Passenger Seats (AC1), Power Driver Seats (AC3), Sports Seats, Leather (AQ9), Selective Ride and Handling, electronic ( FX3), Stereo System with CD, Delco Bose (U1F), and Low Tire Pressure Warning Indicators (UJ6). Additionally, the six-speed manual transmission (MN6) was required.
  • The ZR1 was also fitted with a special LT5 engine (that was unique and limited to the ZR1 coupe.) The LT5 engine was designed with the same V-8 configuration and 4.4 inch bore spacing as the standard L98 engine, but was otherwise an all new Chevrolet/Lotus design with four overhead camshafts and 32 valves..
  • Despite extensive use of aluminum, the complexity of the LT5 engine caused it to weigh just under 40 pounds more than the base model iron-block engine.
  • The LT5 Engine produced 375 horsepower but still managed to avoid the EPA’s gas guzzler tax.
  • The LT5 Engines were assembled by Mercury Marine in Stillwater, Oklahoma, and were then shipped to the Corvette plant in Bowling Green Kentucky for ZR1 Corvette assembly.
  • Chevrolet service departments returned LT5 engines to Mercury Marine for certain repairs. Customers were given the choice of a replacement engine or return of their original engine, if repairable.
  • RPO K05 (Engine Block Heater) was not available when the ZR1 option was ordered.
  • The ZR1 option was only available in the coupe bodystyle.

Notes:

  • For a limited time, Chevrolet dealers could order Corvettes destined for the World Race Series.
  • Merchandising code R9G triggered deviations from normal build, such as heavy duty springs with FX3.
  • Owners could buy sealed race engines from Chevrolet, although modifications to the engine were the car owner’s responsibility. Twenty-three 1990 R9G Corvettes were built.
  • 1990 Corvettes had improved ABS (Anti-Lock Braking System) and improved yaw control.
  • The RPO V01 Radiator and B4P Boost Fan were not optional in 1990 as both were unnecessary due to 1990’s more efficient, sloped radiator design.
  • Corvette did not pace the 1990 Indianapolis 500, but 80 turquoise or yellow “Indy Festival” convertibles with special graphics were built for the event

1990 Corvette

1990 Corvette Recalls

Recall 06e043000

Make: Chevrolet
Model: Corvette
Model Year: 1990
Manufacturer: Honeywell International, Inc.
Mfr’s Report Date: May 19, 2006
Nhtsa Campaign Id Number: 06e043000
Nhtsa Action Number: N/a
Component: Fuel System, Gasoline
Potential Number Of Units Affected: 88303

Summary

Certain Replacement Fuel Filters, Fram Brand Name P/n G3727, With Date Codes X52911 Through X60801 Sequentially Or X600141 And A Mexico Country Or Origin Marking On The Fuel Filter Housing Manufactured From October 18, 2005, Through March 21, 2006, Sold For Use On The Vehicles Listed Above And On Certain School Buses. (To See The School Bus Engine Sizes, Click On “Document Search” And Then “Bus Applications”). The Connector On The Fuel Filter Was Not Manufactured To Honeywell’s Specification. As A Result, The O-ring May Not Seat Correctly On The Fuel Line.

Consequence

This Condition May Cause An Inadequate Seal At The Connection, Potentially Leading To A Fuel Leak. In The Presence Of An Ignition Source, A Fire Could Occur.

Remedy

Honeywell Will Notify Owners And Replace The Fuel Filters Free Of Charge. The Recall Began On October 18, 2006. Owners May Contact Fram Customer Service At 1-800-890-2075 (Option 1).

Notes

This Recall Only Pertains To Aftermarket Fram Fuel Filters And Has No Relation To Any Original Equipment Installed On The Vehicles Listed. Customers May Contact The National Highway Traffic Safety Administration’s Vehicle Safety Hotline At 1-888-327-4236 (Tty: 1-800-424-9153); Or Go To Http://www.safercar.gov.

Recall 07e088000

Make: Chevrolet
Model: Corvette
Model Year: 1990
Manufacturer: Honeywell International, Inc.
Mfr’s Report Date: Oct 19, 2007
Nhtsa Campaign Id Number: 07e088000
Nhtsa Action Number: N/a
Component: Equipment
Potential Number Of Units Affected: 121680

Summary

Certain Honeywell Fram Racing Brand Hp4 And Hp8 Oil Filters That Were Manufactured From May 25, 2006, Through September 14, 2007, And Sold For Use As Replacement Equipment For Vehicles List Above. The Affected Filters Are Marked With A Date Code A61451 Through A72571 Sequentially. The Date Code And Part Number Appear On The Filter Housing. Fram Racing Hp4 And Hp8 Oil Filters Not Bearing A Date Code In This Range Are Not Affected By This Recall. The Gasket Of The Oil Filter Becomes More Pliable Under High Temperatures And Pressures.

Consequence

This Condition May Cause Inadequate Sealing And Loss Of Engine Oil, Possibly Resulting In A Fire.

Remedy

Honeywell Will Replace The Affected Oil Filters Free Of Charge. The Recall Began During November 2007. Owners Can Contact Fram Customer Service Toll-free At 1-800-890-2075.

Notes

Customers May Contact The National Highway Traffic Safety Administration’s Vehicle Safety Hotline At 1-888-327-4236 (Tty: 1-800-424-9153); Or Go To Http://www.safercar.gov.

Recall 90v008000

Make: Chevrolet
Model: Corvette
Model Year: 1990
Manufacturer: General Motors Corp.
Mfr’s Report Date: Jan 16, 1990
Nhtsa Campaign Id Number: 90v008000
Nhtsa Action Number: N/a
Component: Fuel System, Gasoline:delivery:hoses, Lines/piping, And Fittings
Potential Number Of Units Affected: 213

Summary

Fuel Feed And Return Line Connectors Have Incorrect Line End Flare Configurations.

Consequence

Line Ends Could Crack Causing A Fuel Leak That Could Result In An Engine Compartment Fire.

Remedy

Install New Fuel Lines With Correct End Flare Configuration.

Notes

System: Fuel Lines. Vehicle Description: Passenger Cars With Lt5 Engines.

Recall 91v143000 Ea90033

Make: Chevrolet
Model: Corvette
Model Year: 1990
Manufacturer: General Motors Corp.
Mfr’s Report Date: Aug 26, 1991
Nhtsa Campaign Id Number: 91v143000 Ea90033
Nhtsa Action Number: Ea90033
Component: Seat Belts:front:anchorage
Potential Number Of Units Affected: 231833

Summary

Under Certain Vehicle Operations And Occupant Usage Conditions, The Safety Belts Can Lockup Or Jam In The Safety Belt Retractor.

Consequence

If Lockup Occurs, It Is Impossible To Pull Belt Out Of The Retractor. The Occupant Of A Seat With An Unusable Safety Belt Is Subject To Increased Risk Of Injury Or Death In The Event Of A Sudden Stop Or Accident.

Remedy

Replace The Safety Belts If The Lockup Occurs.

Notes

System: Safety Belts.vehicle Description: Passenger Cars.


1990 Corvette Service Bulletins

Service Bulletin 020730024a

Make: Chevrolet
Model: Corvette
Model Year: 1990
Manufacturer: General Motors Corp.
Service Bulletin Number: 020730024a
Date Of Bulletin: Aug 01, 2005
Nhtsa Item Number: 634999

Component

Power Train: Automatic Transmission: Lever And Linkage: Column Shift

Summary

Diagnosis Of Cracked Or Broken Transmission Case. *tt 2006 And Prior Cars And Light Duty Trucks. *tt

Service Bulletin 020730024a

Make: Chevrolet
Model: Corvette
Model Year: 1990
Manufacturer: General Motors Corp.
Service Bulletin Number: 01697
Date Of Bulletin: Jan 01, 2004
Nhtsa Item Number: 10006297
Component: Equipment:electrical

Summary

No Serial Data Communications Using The Tech 1 With A 1986 Or Newer Camaro, Firebird Or Corvette With A 5.0 Or 5.7 Litre Engine. Sit Bulletin 1450640. *tt

Service Bulletin 010729004

Make: Chevrolet
Model: Corvette
Model Year: 1990
Manufacturer: General Motors Corp.
Service Bulletin Number: 010729004
Date Of Bulletin: Jun 01, 2001
Nhtsa Item Number: 622763

Component

Power Train:manual Transmission

Summary

Information Regarding Corvette Zf Six Speed Manual Transmission.

Service Bulletin 9313110

Make: Chevrolet
Model: Corvette
Model Year: 1990
Manufacturer: General Motors Corp
Service Bulletin Number: 9313110
Date Of Bulletin: Mar 01, 1993
Nhtsa Item Number: 39547
Component: Visibility:glass, Side/rear

Summary

Rear Lift Window Hard To Open/hinge Loose To Glass. *tw


1990 Corvette Common Issues

The following list of common issues is intended for individual reference only, and may not reflect the specific issues of every 1990 Corvette. This information comes from a variety of sources including the NHTSA Defects Reports pages. While the intent of this page is to identify the common issues pertaining to the 1990 Corvette (including the ZR-1), it is not an all-inclusive list and should be used for reference only.

Mechanical Issues

Engine

The throttle linkage is known to stick, causing the throttle body to remain open. This creates a potentially serious issue in that it can cause the car to accelerate uncontrollably at ignition, resulting in damage to vehicle and possible driver/passenger injury.

The 1990 L98 Engine is known to have overheating issues.

The vehicle shuts off either when the car is at idle or when decelerating from highway speeds.

Oil cooling lines prone to leak over time, causing oil to cover bottom of car/drip on the exhaust system.

Creates serious potential for engine fire/similar hazardous condition.

Transmission

Transmission O-ring leaks.

Braking System

Anti-lock brakes known to fail. Cause of malfunction believed to be either wheel speed sensor or defective brake rotor.

Uneven braking reported, resulting in the vehicle pulling either to the left or the right during normal braking conditions.

Front brake rotors/pads reported to failure prematurely, resulting in frequent replacement. Early brake fatigue could be the result of improperly operating anti-lock barking system, which was identified as a known mechanical issue on a number of 1990 Corvettes. Additionally, erratic brake response is believed to cause the vehicle to become uncontrollable while driving in wet weather.
Parking brake recalled because of problem with parking brake assembly. The cable pulls loose of the nylon reel resulting in failure of parking brake mechanism. See 1990 Corvette Recalls for more information.

Power Steering

Steering noise occurs when the steering wheel is turned left or right, or when the car is sitting stationary.

Suspension

Fiberglass rear leaf springs prone to breakage causing the rear of the vehicle to sag and/or to drag on the pavement while being driven.

Electrical Issues

ECU (Engine Control Unit/Electronic Control Unit)

Electronic control unit prone to failure, resulting in ignition failure and/or impairing vehicle operation.

Instrument Cluster Module

Electrical problem in sensor unit causes erratic readings from the outside temperature gauge which, in turn, causes the air-conditioning system to operate erratically.

Engine Compartment

Engine compartment fires have been reported – cause unknown, presumed to be an electrical problem. Another possible cause could be a defective hood release cable. There are some indications that the hood release cable rubs the electrical wiring, which could create a fire condition very close to the fuel lines.

Exterior Issues

Windshield Wiper Motor/Drive

Wiper motor/transmission known to fail during normal operation. Although there have been several incidents reported, this malfunction may simply be the result of age and not a specific defect in the design.
Defective windshield wiper relay board.

Windshield wipers reportedly collide and bind, causing assembly to become inoperative during operation which, in turn, can cause serious impairment while driving vehicle in rain/storm conditions.

Tire Pressure Indicator

Low tire pressure system fails as the result of a defective wheel transmitter.

Interior Issues

Passive Restraint System

Airbag deployment has failed on a number of 1990 Corvettes. Despite deployment failure, the sensors indicated that the airbags had been inflated.

Light on dashboard illuminates, indicating that the air bag system is not operating properly. Indicated repair is dealer replacement of the Air Bag Inflator Module.

Seat Belts/Safety Restraints

Both driver and passenger seat belts prone to failure. Seat belts were recalled by dealership. See 1990 Corvette Recalls for more information.

Seat belt retractor locks in closed position/reported inoperable.

1990 Corvette

1990 Corvette Maintenance Schedule

Maintenance Schedule

Schedule 1

Follow Schedule 1 if your car is mainly operated under one or more of the following conditions:.

  • When most trips are less than 4 miles (6 kilometers)
  • When most trips are less than 10 miles (16 kilometers) and outside temperatures remain below freezing.
  • Idling for extended periods and/or low-speed operation such as found in delivery, police, rental or taxi operation.
  • Towing a trailer.
  •  Operating in dusty areas.
1990 Corvette Maintenance Schedule
1990 Corvette Maintenance Schedule

Schedule 2

Follow Schedule 2 only if none of the driving conditions specified in Schedule 1 apply.

1990 Corvette Maintenance Schedule
1990 Corvette Maintenance Schedule

Additional Maintenance and Lubrication

While Operating Your Vehicle

Automatic Transmission Shift Indicator Position – Make sure the indicator points to the gear chosen.
Horn Operation – Blow the horn occasionally to make sure it works.  Check all button locations.
Brake System Operation – Be alert to abnormal sounds, increased brake pedal travel or repeated pulling to one side when braking.  Also, if a brake warning light comes on or flashes, or the anti-lock (if equipped) comes on or remains on, something may be wrong with part of the braking system.  Have it inspected and repaired at once.

Exhaust System Operation – Be alert to any changes in the sound of the system or any smell of fumes.  These are signs the system may be leaking or overheating.  Have it inspected and repaired at once.  Also see “Engine Exhaust Gas Caution (Carbon Monoxide)” and “Catalytic Converter” in your Owner’s Manual.

Tire and Wheel Operation – Be alert to a vibration of the steering wheel or seat at normal highway speeds.  This may mean a wheel balance is needed.  Also, a pull right or left on a straight, level road may show the need for a tire pressure adjustment or wheel alignment.

Steering System Operation – Be alert to changes in steering action.  An inspection is needed when the steering wheel is harder to turn or has too much free play or if unusual sounds are noted when turning or parking.

Headlight Aim Operation – Take note of light pattern occasionally.  If beam aim doesn’t look right, headlights should be aligned.

At Each Fuel Fill:

Engine Oil Level Check – Check engine oil level and add if necessary.  See your Owner’s Manual for further details. NOTE:  A large loss of oil in this system may indicate a problem.  Have it inspected and repaired at once.

Engine Coolant Level and Condition –  Check engine coolant level in coolant reservoir tank and add if necessary.  Replace if dirty or rusty.  See your Owner’s Manual for further details.  NOTE: A large loss in this system may indicate a problem.  Have it inspected and repaired at once.

Windshield Washer Fluid Level Check – Check washer fluid level in container and add if necessary.
At Least Monthly:

Tire Pressure Check – Keep pressures as shown on Tire Placard on the driver’s door (include spare unless it is a stowaway).  Pressure should be checked when tires are “cold”.

Light Operation Check – Check operation of license plate light, side-marker lights, headlights including high beams, parking lights, taillights, brake lights, turn signals, backup lights, instrument panel and interior lights and hazard warning flashers.

Fluid Leak Check – After the car has been parked for a while, inspect the surface beneath the car for water, oil, fuel or other fluids.  Water dripping from the air conditioning system after use is normal.  If you notice fuel leaks or fumes, the cause should be found and corrected at once.

At Least Twice A Year (for example: Every Spring and Fall):

Power Steering Pump Fluid Level Check – Check power steering pump fluid level in accordance with Owner’s Manual instructions and keep at proper level.  NOTE: A large loss in this system may indicate a problem.  Have it inspected and repaired at once.

Brake Master Cylinder Reservoir Fluid Level Check – Check fluid and keep at proper level.  NOTE: A low fluid level can indicate worn disc brake pads which may need to be serviced.  NOTE: A large loss in this system may indicate a problem.  Have it inspected and repaired at once.

Clutch System Service – Manual Transmissions – For cars equipped with hydraulic clutch systems, check the reservoir fluid level and add fluid as required.  All others, check clutch pedal free travel and adjust as necessary.  See your Owner’s Manual for further detail.  NOTE:  A large loss in this system may indicate a problem.  Have it inspected and repaired at once.

Each Time Oil Is Changed:

Automatic and Manual Transmission/Transaxle Fluid Level Check – Check transmission/transaxle fluid level and add as required.  If equipped with manual transmission – check fluid in the overdrive unit and add as required.  NOTE: A large loss in this system may indicate a problem.  Have it inspected and repaired at once.

Tire and Wheel Inspection and Rotation – Check tires for abnormal wear or damage.  Also, check for damaged wheels.  To equalize tire wear and obtain maximum tire life, it is suggested that tires be rotated at 7,500 miles (12,500 kilometers) followed by 15,000 miles (25,000 kilometers) thereafter.  See “Tires” in owners manual for further information.

Brake Systems Inspection – For convenience, the following should be done when wheels are removed for rotation: Inspect lines and hoses for proper hookup, binding, leaks, cracks, chafing, etc.  Inspect disc brake pads for wear and rotors for surface condition.  Also inspect drum brake linings for wear and cracks (if applicable).  Inspect other brake parts, including drums, wheel cylinders, parking brake, etc. at the same time.  Check parking brake adjustment.   INSPECT BRAKES MORE OFTEN IF DRIVING HABITS OR CONDITIONS RESULT IN FREQUENT BRAKING.

Steering, Suspension and Front Drive Axle Boot and Seal Inspection – Inspect front and rear suspension and steering system for damaged, loose or missing parts, signs of wear or lack of lubrication.  Inspect power steering lines and hoses for proper hookup, binding, leaks, cracks, chafing, etc.  (On cars equipped with manual steering gear, check for seal leakage.)  Replace seals if necessary.

Exhaust System Inspection – Inspect complete system.  Inspect boy near the exhaust system.  Look for broken, damaged, missing or out-of-position parts as well as open seams, holes, loose connections or other conditions which could cause a heat build up in the floor pan or could let exhaust fumes seep into the trunk or passenger compartment.

Throttle Linkage Inspection – Inspect for interference, binding , damaged or missing parts.

Engine Drive Belts Inspection – Inspect all belts for cracks, fraying and wear.  Adjust or replace as needed.

Rear Axle Service – Check gear lubricant level and add if needed.  Cars equipped with limited-slip differential should have gear lubricant and any required additives drained and refilled at 7,500 miles (12,500 kilometers).  See your Owner’s Manual.  IF YOU USE YOUR CAR TO PULL A TRAILER, CHANGE GEAR LUBRICANT EVERY 7,500 MILES (12,500 KILOMETERS).  NOTE: A large loss in this system may indicate a problem.  Have it inspected and repaired at once.

Power Antenna – Clean and then lubricate power antenna mast.  The proper lubricant should be used.

At Least Once A Year:

Lap and Shoulder Belts Condition and Operation – Inspect belt system, including webbing, buckles, latch plates, retractors, guide loops and anchors.

Seatback Latch and Recliner Operation – Be sure seatbacks latch using mechanical latches.  Make sure the recliner is holding by pushing and pulling on the top of the seatback while it is reclined.  See your Owner’s Manual for seat operating information.

Spare Tire and Jack Storage – Be alert to rattles in rear of car.  Make sure the spare tire, all jacking equipment, any tire inflator and any covers or doors are securely stowed at all times.  Oil jack ratchet or screw mechanism after each use.

Key Lock Service – Lubricate key lock cylinder at least annually.

Body Lubrication Service – Lubricate all body door hinges including the tailgate (if equipped).  Also lubricate the body hood, fuel door and rear compartment hinges and latches including interior glove box and counsel doors, and any folding seat hardware.

Starter Safety Switch Operation – CAUTION: Before performing the following safety switch check, be sure to have enough room around the car.  Then, firmly apply both the parking brake (see your Owner’s Manual for procedure) and the regular brakes.  Do not use the accelerator pedal.  If the engine starts, be ready to turn off the ignition promptly.  Take these precautions because the car could possibly move without warning and possibly cause personal injury or property damage.  On automatic transmission cars, try to start the engine in each gear.  The starter should crank only in “Park” or “Neutral”.  On manual transmission cars, place the shift lever in “Neutral”, push the clutch halfway and try to start.  The starter should crank only when the clutch is fully depressed.

Steering Column Lock Operation – While parked, try to turn key to “Lock” in each gear range.  The key should turn to “Lock” only when gear is in “Park” on automatic or “Reverse” on manual transmissions.  On cars with key release lever, try to turn key to “Lock” without depressing the lever.  The key should turn to “Lock” only with the key lever depressed.  On all vehicles, the key should come out only in “Lock”.

Parking Brake an Transmission “Park” Mechanism Operation – CAUTION: Before checking the holding ability of the parking brake and automatic transmission “Park” mechanism, park on a fairly steep hill with enough room for movement in the downhill direction.  To reduce the risk of personal injury or property damage, be prepared to apply the regular brakes promptly if the car begins to move. To check the parking brake, with the engine running and the transmission in “Neutral”, slowly remove foot pressure from the regular brake pedal (until the car is only held by the parking brake.)  To check the automatic transmission “Park” mechanism holding ability, release all brakes after shifting the transmission to “Park”.

Underbody Flushing – At least every spring, flush from the underbody with plain water any corrosive materials used for ice and snow removal and dust control.  Take care to thoroughly clean any areas where mud and other debris can collect.  Sediment packed in closed areas of the vehicle should be loosened before being flushed.

Engine Cooling System Service – Inspect coolant and freeze protection.  If dirty or rusty, drain, flush and refill with new coolant.  Keep coolant at the proper mixture as specified in your Owner’s Manual.  This provides proper freeze protection, corrosion inhibitor level and engine operating temperature.  Inspect hoses and replace if cracked, swollen or deteriorated.  Tighten hose clamps.  Clean outside of radiator and air conditioning condenser.  Wash radiator filler can and neck.  To help ensure proper operation, a pressure test of both the cooling system and cap is also recommended.

1990 Corvette

1990 Corvette DIY Service Guide

Battery & Charging

Inspection & Replacement of Battery, Factory Battery Specifications, Replacement of Alternator/Generator

Belts & Hoses

How to Replace Drive Belt(s), Inspection & Replacement of Upper/Lower Radiator Hoses

Braking

Inspection & Replacement of Brake Pads, Inspection & Replacement of Front/Rear Brake Rotors, How to Replace Brake Calipers, How to Bleed Brakes, Inspection & Replacement of Master Cylinder

Heating & Cooling

Inspection & Replacement of Radiator, How to Replace the Heater Core, Inspection & Replacement of Upper/Lower Radiator Hoses, How to Flush the Cooling System, How to Replace the Water Pump, How to Replace a Thermostat.

Emissions

Location of, Inspection & Replacement of Oxygen Sensors (Upstream/Downstream), How to Replace the EGR Valve, How to Replace the Smog Pump.

Filters/PCV Valves

Location & Replacement of the Following Filters: Oil Filter, Fuel Filter, Transmission Filter, PCV Valve.

Ignition & Tune Up

How to Replace the Ignition Coil, How to Replace the Ignition Switch, Inspection & Replacement of Sparkplug Wires, Inspection & Replacement of Cap & Rotor, How to Replace Sparkplugs, Engine Firing Order, Engine Timing.

Relays & Sensors

Location & Replacement of: Mass Air Flow Sensor, Oil Pressure Sensor, Engine Temperature Sensor, Ambient Air Temperature Sensor, Fuel Pressure Sensor, Oxygen Sensors (Upstream/Downstream).

Suspension & Steering

Inspection & Replacement of Upper/Lower Ball Joints, How to Replace Control Arm Bushings, How to Replace the Power Steering Pump, Inspection & Replacement of Front Shocks/Struts, Inspection & Replacement of Rear Shocks/Struts, How to Replace Inner & Outer Tie Rod Ends.

Starter/External Engine

How to Replace the Starter Motor, How to Replace the Starter Solenoid, How to Replace the Drive Belt Tensioner, How to Replace the Idler Pulley, Location of, Inspection & Replacement of Engine (Motor) Mounts, How to Replace the Oil Pan Gasket, How to Replace the Oil Pump.

Transmission & Clutches

How to Change the Transmission Filter (Automatic Transmission), How to Replace a Clutch (Manual Transmission).

Source Material:

  1. The Pocket Book of the Corvette: The Definitive Guide to the All American Sports Car – Copyright 2003, Barnes & Noble
  2. CORVETTE: Sports Car Superstar – Copyright 2005, PIL – Publications International, Ltd.\
  3. Corvette Black Book – Copyright 2009, Michael Bruce Associates, Inc.
  4. The Complete Book of Corvette, Every Model Since 1953 – Copyright 2005, Mike Mueller – MBI Publishing

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