Thank you for the additional items, noted!
Are you suggesting that I start another post asking for the items that consistently work well with no failures? Show me another production vehicle without a failure and a following like the Vette has? Where does all the love come from? There will be plenty of good left to say I'm sure!

 

The "Multec" fuel injectors on the 88-91 L98 engine usually go bad at around 75000 miles or so. Because of the design, these fuel injectors can't be rebuilt and have to be replaced.

The recommended replacement is the Ford Bosch style from Five-O-Motorsports (questionable reputation) or, the NEW improved Silver Bosch style Accel fuel injectors from Summit Racing.

 

1) Roof leaks
2) Optispark Failure, Optispark more prone to failure in early LT1's (non-vented vs. Vented), typically caused by failure of water pump.
3) Sport seats lumbar support - pump failure
4) Headlight bushings
5) FX3 Ride Control failure
6) Hood release cable may eventually break

 

Don't forget the ever popular 80 psi oil pressure reading.

I don't recall reading about the Bose speaker problems.

The 'beautiful' brown color the valve covers develop over time.

 

Interior door panels. Many different years, mine is a 94.

 

bad weatherstrips
4+3 OD failure
"morning sickness" ps rack issues
rear wheel bearings
paint
heater core replacement
oil pressure sending unit (80 psi reading)
digi dash failure
bose stereo
easily cracked interior plastic
super clogged radiator / a/c compressor gap (not really a problem, but a neglected service)
alternators
almost impossible to change the tail light bulbs in the early C4's (unless u have super skinny arms or a trained squirrel)
PITA to remove valve covers to replace valve cover gaskets

sorry for repeats, and I am sure there are more

 

Are you mostly interested in general design flaws? I think we should keep in mind that our c4 Corvettes are at least 11 years old. We also need to keep in mind that they are mass produced Chevrolets. The strange thing about mass produced cars are that one car can go a lifetime without failure of any kind, and another can be riddled with problems from day one.

Then there is the factor of previous owners. How much was the car driven? How was it driven? What modifications were made? Who made those modifications and did they know what they were doing? All of these things can contribute to factory parts failing. When I bought my 96, it had 24K on it. Driven about 2.5 k per year. the first thing to go was the water pump, dried inner seal. The opti was fine due to the improved vented design. Then the clutch. Recently the clutch fork and pivot ball. I think the previous owner put 24K on it 1/4 mile at a time.

Weather stripping? Heck yeah, after 11 to 23 years, the stuff is going to rot, whether it ever sees rain or not. Moving parts wear, can't change that. Gaskets wear out out also, fact of life. "Corvette Fever" magazine has a section in the back about c4's, it's called "Wear and Tear". Go figure. While being one of the most revered sports cars ever, it is consequently one of the most abused. Beyond the "mystique" a Corvette is still "a car".

 

You can go ahead and start another post,it would be a short one.Calling the cars junk was a bit of an over statement but Ive had my 84 for 20+ years and Im the only thats worked on it so I know first hand how cheap these cars were made.One more item,the driver side door panel at the top warps and doesnt fit right,the harmonic balencer ring will slide back on the main hub.Ive got more,just give me some time to think.

 

Fuel injectors really seem to have had a lot of trouble
Continuing to develop a trend, thanks for the new items!
Very helpful, elaborate on the oil pressure problem?
Seems like your not alone.
The repeats show consistency! Thanks for the additions
The only resriction is that I'm stopping with the C4, no further. The C5 and C6 list will be a book not an article Thank you for the input!
I must show you great respect, anyone that does thier own repairs is without a doubt in the know! Me being a C3 guy I learned more about them after I started my restoration of a 72. I don't have total production numbers in front of me, but GM sold alot of "junk" in the C4 series. During this 11 years of production did the C4 improve? Of course the first year of a new design change there is apt to be many kinks.

 

Yeah, but Dude if you really want to compare cheap cars the Japanese cars are way ahead of American cars. How many "nipper" cars over 23 years old would you own?

 

- The 92 and 93 C4s tend to have ECMs that go bad. (same ECM unit for those two years) The mother board develops connection problems, warps from heat in the engine compartment.
- Of course, the opti can be a source of problems.
- The Bose sound system seems to not be very durable,

 

Several people have touchced on some of the following areas and I simply am expanding on such topics.

Regarding the Optispark, here's a little more detail about it. All L-98 engines do not have an Opti - thank goodness. The LT1's and LT4's have the Opti, the LT5's don't. The Opti cannot handle any type of wetness. If they do get wet, kiss them goodybe and if you take the car to a local mechanic or Chevy dealer, you're looking at around a $1,200 to $1,500 bill. A heck of a lot must come off just to reach its hidden location. When they do go and they all at some point eventually will, your best bet is not a stock replacement. MSD makes one and from what I've heard, they are much more impervious to water than its stock counterpart.

The radiator design... This ingenious radiator design causes a huge build-up of debris, which in turn, compromises air flow. This causes the engine temperature to always run hotter than it should. A once a year clean-out of this debris will cure this incessant heat problem. In addition to this problem, the stock radiator is adequate, but not too great. I'd say that most people replace the stock radiator with an aftermarket unit, such as Dewitts. There is a huge difference in engine temperature once the switch is made. New technology has definitely positively impacted the C4, especially in regard to its ability to keep the car cool.

The Bose system in the C4's suck wind. The usual culprit are the amps. They can run about $150 apiece, so when someone's system begins to show its age, most people simply replace the entire system with a modern unit, many opting for an MP3/DVD player.

The stock brake configuration/system in the C4's are actually quite good, but anything can be made better. Many enthusiasts upgrade to a system that has larger and stronger rotors, additional pistons, etc. Tests prove that the upgraded brake systems actually do stop the car in less distance, are more reliable, sometimes have less brake dust and the components wear out much slower than that of a stock system.

The early C4 alternators worked very well, but in the latter part of the mid 80's they decreased the amperage. I'm sure they had a reason for doing so, but they didn't work as well as the earlier years. Many people replaced the stock unit for a Powermaster or similar unit whose power was considerably increased.

The stock shocks on non-Bilstein equipped cars were nothing but crap. In my opinion, Bilstein is one of the top rated shocks and GM cheaped out their customers when they installed, I believe Gabriel shocks. I may be wrong here with the name, but nevertheless, the factory installed shock was crud. Many people replaced this shock with a set of Bilsteins, Koni, or anything rated well. Even KYB is an excellent alternative, if money is a factor.

Getting off the parts topic for a moment... Many people shy away from purchasing a Corvette because they erroniously believe that to insure their prospective Corvette would cost a bundle. This myth cannot be further from the truth. There are numerous companies that would love to insure your Corvette and would do so for a very reasonable, inexpensive price. The only conditions(s) that exist in most of these policies is that: 1) you must have a second car and that the Corvette cannot be your primary car for transportation, 2) your total yearly mileage can be limited. Many companies limit the amount of driving you can do in your Corvette. The offer varies company to company, but the mileage is usually a choice of 2,500 miles, 5,000 miles and some even offer an unlimited amount of driving. You need to speak to a representative or ask for a contract and read the fine print. The average cost to insure a C4 for say $12,000 to $15,000 hovers between $200 and $350 a year, depending where you go. If you're under 25 years old, these figures will change (be higher) considerably.

I don't know about the later C4's, but on the earlier models, the scissor style hood lift assist is something out of the stone age. Many people replace it with a gas-charged assist unit which makes opening and closing the hood a one finger job. Without the gas assist, two hands and a good amount of strength are needed.

I hope this helps.

 

All LT1's and LT4's have the Opti, LT5's don't.

My policy must be the exception the the rule. My insurance actually decreased when I made my Corvette the primary car.

 

Thx. I changed my post to reflect the correction so when someone reads it, they read correct info.

 

Yes they did...........Towards the end of C4 production the cars did get better but then again GM had 13 years to work out the bugs.

 

"floppy ear" sun visors and oil leaks on LT1. Loose door panels.

 

My list of problem areas in early c4's
1. 86-91 the cs-130 alternator. This alternator has diodes in close proximity to the rear case bearing and poor cooling compared to newer designs. The rear bearing and electronics have a very high failure rate.
2. 89-91 corvette rochester multitech injectors. This injector was not designed for blended fuel use. (alcohol) The injector coil insulation fails and the injector shorts out. These are guaranteed to die in all cars equiped with them.
3. 84-89 Bose speaker amplifiers have a very high failure rate.
4. 84-93 94? (Sport seats) These seats have cronic pump diaphram and lumbar bladder failures. The factory material these are made of are of poor durability.
5. Digital dashes used from 84-89 develop poor ground circuits at ground points in the car. This which causes all sorts of issues with the dash cluster. Very early digital dashes have a high failure rate. The last year or two of production became pretty reliable as far as the cluster goes. The ground issue is with all.

 

Shocked that no one has mentioned this one, minor issue of course but very common for the mast ribbon to break.

 

It looks to me, that the C4 list will be considerably longer than the earlier era's!

Post from the C1/2

"This started as a way to help answer the same few questions posted over and over. I can't tell you how many"what to look for"," what should I watch out for when buying a Corvette"posts I've read.You can find plenty of stat's and documentations but I'm not aware of a "written list" of specific trouble spots for each different era. Just thought that it would be nice to have some type of punch list. I stopped with the C4 only because I'm not at all familiar with the newer models. Not looking to write a book, only a helpful list! "

 

The ZF6's reverse switch to activate the reverse lights fails on most cars.

The fuel injectors on the earlier cars weren't made to work with ethanol in gasoline, because it didn't exist at the time. So they seem to be almost certain to fail with enough exposure.