Common Corvette C5 problems and solutions (2023)

Common Corvette C5 problems that, if addressed early, can save you money and expensive damage.

battery drain
Many C5s came with AC Delco Freedom batteries, which tended to break the case near the battery posts. Battery acid leak would run down the side of the battery, through the funnel-style battery holder, directly into the PCM and wiring harness. It can also get into air conditioning lines. I believe it is the vacuum lines that control the movement of the interior vents and often by default the system closes the defrost vent. Sometimes there was damage to the car, sometimes not. The worst would be changing the battery, PCM, electrical harness, removing rust from the frame to repaint it, changing the air conditioning lines and possibly changing another computer as well. This mostly happened on early C5s because later C5s used a gel battery that didn't leak, but I think the problem reappeared on the '04 or '05 models.

See this on every car you look at. Use an 8mm wrench, preferably a ratcheting version with a closed end, to remove the battery cables. You will also remove a retaining block on the front of the battery. You need a long way to reach it. The battery basically stands out right away. Also remove the black plastic battery compartment. Look under the tray for rust or white dust. Both indicate battery acid damage. It would probably be best to move on to the next Corvette, unless you don't mind doing this repair in the future. It is possible that the car issues codes for no apparent reason.

No matter which Vette you buy, be sure to replace the battery with a gel battery like the Optima Redtop, available at CostCo for $100.

Grounding Problems aka CRAZY Electric Leprechauns!
Bill Curlee has a great thread on the problems corroded grounds can cause and how to clean floors. The most problematic grounds are behind the headlights on both sides. Check out Bill's thread for detailed information: Go ahead!
Here are all the reasons: Go!

water consumption
Water leaks have a number of ways to get into your car and none of them are AFAIK very difficult to repair. Proper adjustment and maintenance will prevent most leaks.
Bill Curlee's thread on finding and cleaning udders and sealing door hinges.
Here are some TSBs from CorvetteActionCenter.com:
1997-1998: Service Bulletin: Door Glass Water Leak (Seal Break Clip)
1997-2002: Service Bulletin: General Guide to Water Leaks
1997: Service Bulletin: Water drops in aft compartment after opening hatch/window

seating
Corvette seats are finicky.

If you slide it hard on the pad, it could break and cause it to wobble from side to side.

Leather is cheap and there is little protection for it. It wears down and cracks, which is normal for cheap leather.

The wire springs in the seat pan and the rods in the seatposts can also wear down the foam and leather, but this can be remedied by placing a layer of burlap between the springs and the foam.

Check the black plastic trim at the bottom of the seat to make sure it is snug against the leather and not cracked. The older plastic bezels tended to come loose from the seat, but could be pushed in. Newer plastic trims can be used as a direct replacement but may require sanding down one of the plastic pegs or drilling a hole in the leather.

The seats tend to rock back and forth about 1/4 inch under acceleration and braking. It can be fixed, but GM won't fix it. Some lucky owners are able to have the dealer replace the frame under warranty. Rocking the seatback forward during braking is normal and not considered a problem.

Here are some fixes:
Corvettemechanic.com --- Must be a member
swing seat accessory

Choice of seat
Take the sports seats. Sports seats have a hole under the headrest. Some people use harnesses to run through these loops. The seat and foam structures on both seats are interchangeable. The wire harness strap holes can be installed with Ford wire harness cutouts. Ask the dealer about this, they should know what it is without a part number. The foam on a standard seat needs to be cut and sewn, but it's an easy job.

headlight frame connector
There are 1-1/2-inch sockets on the headlight bezels that would fall off on older Corvettes. The newer style sockets have a twist lock to keep them from falling out, but they also require new bezels. Only the new bezels and sockets are now available and are compatible with older C5 models.

headlight kit
Headlight motor gears are made of plastic and will wear out over time. Ice, heavy Euro headlights, or twilight projectors and monitors wear gears down quickly. Fortunately, Rodney started selling aftermarket brass gears a few years ago, check out his website. Corvette America and probably a few other sellers are now selling their own copy of their brass gears. Here is a thread showing how to change gears.

ceiling noise
If you buy a coupe with a removable roof, you should expect wind noise and some squeaking. Wind noise will never go away completely, but if it does squeak, it can be eliminated by applying a thin layer of dielectric silicone grease to the sealing strip. It also prevents cracking, that is, with all-weather seals on all cars.

jingle
In cold weather, the rubber hood bumpers can also rub and rattle the hood. Adjust the rubber stops and lubricate them so that when you pull on the corner of the hood it does not go up but the hood closes.

power train talk
The valve train makes a lot of noise at idle. It may sound like a sewing machine. Upgrading valve rocker arms to true shaft mounted adjustable roller rocker arms, when properly adjusted, can help eliminate valve train noise. Installing a large cam and stiffer valve springs makes for louder noise.

On vehicles with a manual gearbox (M6 or M12), the gearbox makes a clang noise when going out of line. It is normal. It's the noise from the release bearing. Sometimes you hear a horrible noise when you turn off the engine. If you step on the clutch pedal while parking the car, you won't hear it.

I checked by lightly sanding my rotors with steel wool. Maroon paper is recommended, but I haven't tried it yet.

If you insist that the problem is warping, do not spin the rotors, as thinner rotors warp more easily. Recapping the rotors is only a temporary solution that is less effective each time you recap the rotors due to the reduced heat capacity of the rotors. Rotors are available from Napa and RockAuto for $25.

Worn front sections and rocker panels
Checking for scratches is an easy way to tell if the car has been well cared for. It is almost impossible not to scratch the front, but there are two metal clips on the bumper bar to prevent scratches to the bumper. The bumper itself must not show any scratch marks. Check the lower edge of the bumper and the lower corners of the bumper. If the crash bar gets scratched up enough, it will eventually wear down to the point where it will need to be replaced. It costs about $220 for slider bars, nut inserts, bolts, and insulators and they can be changed in a few hours. Just be sure to reconnect the hoses and electrical connection to the A.I.R. Bomb.
Here is a list of ALL the parts you will need to replace the crash bars and side air deflectors:
Part #------Quantity---Description
10188023---001---Insulator (goes to the bottom of the radiator)
10278679---001---Insulator (goes to the bottom of the radiator)
10278679---005---Mutter
10400765---001---Plate (the actual crash bar, unpainted)
10419312---001---Painel (Luftabweiser)
ctor)
10419313---001---Panel (air guide plate)
11515638---010---nut specification
11515757---010---Loja-Metro
10281487---010---Mutter
You don't need to replace all of these parts, and there will be some leftovers, but they will get the job done.

Rocker panels tend to rub on elevators and large speed bumps.

A&A Corvettes invented two products to prevent damage from both types of scratches. They have wheels that attach to the railing, allowing the car to roll on sidewalks instead of wearing down the railing. The spoiler will still scratch, but the spoiler is an inexpensive wear part that can be replaced in just 2 minutes without a lift or jack. They also make two aluminum strips that secure the frame next to the sills and eliminate scratches in place of the sills. Neither device is visible unless you look under the car, and they're unobtrusive enough to ignore anyway. When you see these installed devices, you can be sure that the owner has taken good care of the car. Without this added protection, expect to have to replace the skid bar and repair the side panels multiple times over the life of the car. NOTICE: This will not prevent all scratch damage, it will only lessen the chance of it happening and reduce the damage when it does. Low headers are likely to still get scratched.

hood seal strip
The sides and rear of the convertible top compartment are equipped with factory sealing strips. The front remains open. Many homeowners install a fence strip along this leading edge. You may not even notice it as it looks identical to the rest of the timeline. This extra amount of time helps keep your engine bay clean and can also help your air intake system perform better. This is another sign that the owner has taken good care of the car. The engine bay remains reasonably clean, but that's the "extra step."

air conditioner
There are two types of climate controls. One is manual with push buttons and the other is a dual zone electronic system. The two zone system, although more expensive, is not as reliable as the manual system. A leaking battery can affect both systems. A strong system is when the fans cannot be interchanged.

Over time, and especially in humid climates, the system can cause condensation to form on the passenger-side carpet. There are three udders under the dash on the driver's side. There are indentations on the bottom, similar to real udders. Squeeze and massage udders vigorously until dirt falls off. Stop laughing!

If the purge settings cannot be changed, it is likely that the vacuum line is loose, clogged, or faulty. Keep reading!

noisy steering wheel
When turning the steering wheel, a screeching noise can be heard. It's just the plastic surfaces rubbing against each other. A dash of lube fixes that.

Squealing/squeaking/broken wheel bearings
Drive slowly, better yet, drive slowly with the windows open in a quiet place. Hear the wheels screeching. Try turning in different directions. If you hear the rear wheels screeching, the wheel bearing may be worn. A replacement bearing is listed for $600, but can usually be found for $400 to $450. I heard that AutoZone has a better replacement for $126 from a company called Timken. The part is easy to replace if you can separate the ball joints. I had to buy a special tool from Kent Moore to make my own. This problem can certainly persist for a few months, but eventually it becomes annoying. Seems to be a common problem, particularly with the rear wheel bearing. I have never heard of the same car being affected twice. So once you fix it, you'll probably be fine for life. Several cyclists replace their wheel bearings every year.

A broken emergency battery clip can lead to a misdiagnosis. Be careful when removing and replacing the rear rotors.

you've been drinking
Many late 2000-2001 brackets burn a lot of oil if the engine is constantly held above 4000 RPM. This is caused by ring chatter, which allows more oil to seep into the oil scraper rings, but doesn't seem to cause additional wear on the engine. Chevrolet rebuilt and replaced engines for owners who complained of excessive oil consumption. Their policy is that while the engine doesn't normally run like this outside of racing, it's the owner's prerogative to ride in second gear at all times if he so desires. it is under warranty

The PCV system also tends to suck oil into the intake at high RPM. There doesn't seem to be any problem other than a little mess in the intake manifold. The latest PCV system can be installed, but this requires removing all components at the top of the engine valley. Usually only pilots worry about rabies. Several generations of PCV systems have had the problem and as of this time, December 2004, the PCV system is still sucking oil into the intake.

The oil suction problem leads to carbon deposits in the cylinders. The dealer sells GM Top End Cleaner and Napa sells SeaFoam. Top End Cleaner is not available in some smoggy states like California. Thread a hose from the bottle into the PCV system port behind the passenger side throttle body. Start the car and slowly suck the solution into the engine. Do not drive too fast, otherwise the engine may stall. Once the solution is gone, stop the engine for > 4 hours, preferably 12 hours. Be aware that when you restart the engine there will be a LOT of smoke!

Oil suction can be avoided by installing a collection container. AMW and Greddy make catch cans, but a homemade catch can can be built using a Campbell-Hausfield Air Tool Oil Separator available at most hardware stores, including AutoZone. The AMW and Greddy cans are ~$100 but look great. The CH can is $15-25 for all the parts and you can see how much oil is in it.

Overheating and burning smell
Although the engine can get as hot as 220, even 240 degrees Fahrenheit, this is normal. The radiator keeps the engine cool enough unless it is blocked. Reprogramming the PCM allows the fans to turn on sooner. If the fans are also cooling a replacement oil cooler, make sure the oil occasionally reaches 220 degrees to allow condensation and fuel to evaporate. Fan settings and oil thermostats are two different ways to do this.

It is not uncommon for plastic bags to get trapped under the front bumper and cover the radiator, causing the car to overheat. If this happens, take a quick look under the bumper and remove anything under it. The bags sometimes get stuck in exhaust pipes and cause a bad smell when burned.

steering column locked
All C5s, especially C5s with a manual transmission and early C6 steering columns, tend to lock up and stay locked up. It can normally be unlocked once, but only once. Some owners claim that jerking the steering wheel hard can unlock it. Dealers can disable the lockout mechanism with a modified lockout plate. This is currently the only real method of disabling the locking mechanism. Basically the wheel will still try to lock, but there is nothing to lock. It's like a door latch with a slot in the door frame. There is a $100 kit that disables the steering column lock and is easy to install, but enough vibration from the car can cause the lock to fall off the lock plate, even while driving!

GM has a part (#88952428 or 88952428) with a different harness jumper and lock plate. I don't know what the difference is between the kits.

After reading some posts the C5 and C6 manual transmissions are still at risk even with the lock off. The lock can vibrate over time and get stuck in the strike plate. Recalled automatic transmission cars and new cars do not have backing plates, so they are safe. Others on the forum and my own personal project provide more information on how to COMPLETELY disable the steering column lock. Until then, here are some
Some links on the subject:
Corvette Forum - Steering Column Lock Harness Installation K
Corvette Mechanic - A4 non-locking column plate --- must be a member
Corvette Forum - Also with CLB of new column lock!
Corvette Forum - Has anyone else hit the pillar lock?

faulty gas meter
If you have bad gas (phew), the fuel sender can be affected by the high sulfur content in the fuel and cause the gauge to go blank. The car still runs normally and the fuel gauge works again when you use better gasoline and comes on normally when you restart the car. It is better to use a good gas. Some people have had luck running a fuel filter cleaner through the gas tank. New fuel gauges sometimes correct this problem. This topic contains many ideas about what might be causing the problems, how to avoid them, and how to fix them. He also points out how the fuel tanks and transition piping differ from the latest C5.

noisy fuel pump
There are two fuel tanks and two fuel pumps. A fuel pump pumps gasoline continuously from the passenger side tank to the driver side tank and is quiet. The main fuel pump is located just behind the driver's seat and can be noisy, especially in early C5 cars. This is normal and does not indicate a fuel pump failure. Chevrolet released a bulletin on how to better isolate fuel pump noise. That's just an annoyance. A newer, quieter pump can also be installed.

Extremely high oil pressure
The oil pressure sensor may fail, but it's still good to drive. Turn off the car but with the key in the "on" position and check the oil pressure gauge. It should show "0". If the oil pressure sensor is faulty, it will show a positive reading. The oil pressure sensor is located behind the intake manifold and requires the intake manifold to be relocated. The transmitter costs about $40 and has the part number 12573107 or 12562230.
like one

suspension winches
In cold weather, you may hear suspension creak when going over speed bumps. To correct this, clean (optional) and lubricate the stabilizer bar bushings. The adjustable metal stabilizer links on the Hotchkis and T1 bars can also make loud clicking noises. Most adjustable end links are initially quiet, but over time they wear out and become noisy. Lubricating and protecting the end links from dirt can prevent wear.

hard change
The gear stick on manual Corvettes needs a strong arm to shift gears. You really need to make sure the shifter is in full first and reverse or it will shift when you release the clutch. It's not the car, it's the driver.

Manual Transmission – Changing the transmission fluid often helps with shifting. Early transmissions have paper o-rings which require Dexron III compatible fluids (usually organic) as some plastics will destroy the paper o-rings and subsequently the transmission. Later transmissions and all rebuilt transmissions have Kevlar/carbon fiber parts that allow the use of synthetic fluids. I believe the 98-00 transmissions have paper pad rings. Safe transmission fluids seem to be: GM Synchromesh PN # 12345349, Honda ATF-Z1, Royal Purple Synchromax, Amsoil ATF, O'Reilly Dexron III ATF. The following transmission fluids may not be safe for early transmissions: Redline D4 ATF, Mobil 1 ATF, Royal Purple Max ATF.
Related topics:
LS1.com - End of Speculation: Blocker Rings, Who Failed With Them?
LS1Tech.com - End of Speculation: Locking Rings, Who Missed Them?
Mobil 1 synthetic ATF for an M6?

When it's particularly hardcapaIn 2nd or 4th gear, the synchronizers may be worn or the forks bent. DO NOT force gear into gear. Abuse creates and exacerbates this problem. You can still drive, pretty good, without synchronizers... or clutch if you know how to set the revs.

Some aftermarket shifters make it easier to make sure it's fully engaged and prevent gear screeching, but they also vibrate and require more effort.capa. The standard shifter features a weight tuned damper that changes vibrations at an inaudible frequency. The shaking doesn't bother some people, and there are a few solutions.

hot ass
The differential may leak from the side covers. The problem has to do with the design. The edge of the box is not wide enough to make a proper seal with the lid. Deck sealing can be successful, but many dealers do not use the correct sealant.

Inner/outer tire turning
If a tire spins while spinning, adjust the friction modifier ratio. Royal Purple, Amsoil, and Redline aftermarket gear oils do not require an additional friction modifier. The GM friction modifier is PN #12377916. Too much friction modifier and the inside tire will spin/jump/jump. Too little friction modifier and the outside tire will spin/jump/jump. - Thanks, Russ!

hoops jump
Tire hops under hard acceleration in cold weather are common, although the same tires won't hop in warmer weather. Tire rubber looks like a spider web when viewed through a microscope. Typically, pieces of this cloth are attached to objects on the ground and stretch until the car rolls forward or the cloth tears, causing the tires to skid. I think when it's cold the grid is too tight for any of these events to happen, so the tires bounce. For more information, read Performance and Racing Tires: Using Tires to Tune Grip and Balance. I haven't read it, but if you do, please let me know if my guess is correct. I found a few stories on Google about people curing wheel lean with stiffer (rebound) hubs and/or shocks.

internal rattles
The visors can make a noise when raised, but when you fold them down, the noise disappears. Pushing on the mirror cover seems to fix this. Try sticking a piece of felt or Velcro between the mirror and the cover to see if that solves the problem. Caravaggio also makes aftermarket leather visors, but they are $400.

The stereo is Bose, and in keeping with the historically poor build quality of Bose products, Bose has decked out the Corvette with Bose badging on the door speaker covers that rattle when you play bassy music. There's no Bose system that delivers good bass, but the system manages to shake the badges when playing country, hip hop, or techno at moderate volumes. Check for this problem by having yourself and a passenger place your finger on the badges while the music is playing. Paste the badges to fix them.

If the ceiling is not tight enough, it will shake. There are adjustment screws in the roof to make this adjustment.

belt squeak
In cold weather the belt may squeak. AutoZone Goodyear Gatorback belts won't squeak.

sticky luke
In cold weather, the hatch may open slowly or not at all. Spray bars with silicone grease until they rise properly. If the brackets won't hold the hatch, try lubricating the support rods.
1997: Service Bulletin - Flap does not appear when activated in cold weather

rocker failure
Needle bearings in OEM rocker arms have been known to fail. The problem is usually noted by added valve train noise and stuck needle roller bearings in a magnetic oil plug. Nasty Performance rebuilds OEM rocker arms with Harland Sharp bearings. This seems to be one of the best solutions, as the stock rocker is very good at high revs. Most aftermarket rocker arms are heavy and require grinding of the valve heads and covers to fit. Harland Sharp rockers are currently having issues with their C-clip mounts falling off and causing problems on the trail. I will go ahead with this issue as I have several HS rockers sitting on my shelf waiting for this issue to be resolved. Here are some links:
LS1Tech - EMERGENCY!! ROCKER! Help ASAP!
LS1Tech - Harland Sharp Balancín-Fehler
LS1Tech - To install or not to install HS rockers?

Other information
training

active stability control
This way you stay in control of the car even with really stupid stunts. It doesn't violate the laws of physics, but it does keep the car in the direction you're driving. You can still slide off the road, but at least the car will be pointing in the direction you drove! One of the sensors is located around the passenger seat and must be considered when installing a racing excavator. If you tamper with this sensor, Active Stability doesn't know how to balance the car and can be very dangerous. Active Stability was released around 1999.

raise
The C5 was the first car with hydroformed frame rails. Hydroformed rails are quickly becoming a common platform for new cars, but few shops are prepared to lift these vehicles. The C5 requires an adapter for regular outlets and risers to fit the outlets. Make your own adapters using a hockey puck (or two) with a 1 1/2" eyelet threaded through the center. Insert eyelet through slot at connector point, rotate 90 degrees, place connector under, fit the adapter and move the jack out of the way...if you can get the jack under the car you may need to use ramps the C5 is so low that most people build their own ramps out of wood...the ramps Rhino's are too steep.

key ring
Basically, there are two different types of keychains that are not compatible with each other.
97-00 but 00 does not have passive blocking function
01-04

plugs
OEM platinum spark plugs, along with other spark plugs, have had issues with disks falling out. I have an image of lost disks in this thread. This topic describes some of the problems with using platinum and a recommendation for using silver-tipped connectors. Basically, of all spark plug tips, platinum is the worst conductor, copper is good, iridium is even better, and silver is the best. Don't take my word for it, do some research as of this review. In terms of longevity, platinum, iridium, and silver have an advantage over copper, but spark plugs fail after ~10,000 which would negate the difference corrosion would make, and no spark plug will perform well after 100,000 miles. .

To make replacing the spark plugs easier, get the Twin Twist Spark Plug Tool and remove the coil assemblies. Here's everything you need to know about changing spark plugs: Go ahead!