Hi,

I will be selling my 1980 C3 and looking for a C4. The 1980 350 Auto is just not a car that I can take on a 500 mile one way drive. For one the gearing is just not meant to do 70-75 all day long. Runs hot on summer days with the AC on. So how reliable are C4's? Are certain years better than others? Is it a car you can drive 75 mph all day long with the AC on? Or do I need to go C5?

 

"How reliable" is kind of a silly question. These cars are all over 25 years old. Most will have old age issues, and some will have more than others.

I've driven my 94 up and down California (400 miles each way) in 100F+ weather with the A/C running without issue. I've never driven my '95 that far in one go, but I've done plenty of 100-mile commutes in it in 80F~100F weather.

The C5 is a fantastic car. GM took everything they learned from the C4 and made it better. If it's in your price range, a C5 might be a better choice. There's also generally more support for the platform in terms of replacement parts. Plus the C5 uses like 1500 less parts overall than any C4.

I love the C4; for the price it's an absolute bargain. But you need to understand that these are old cars. If you're not willing to wrench on it and you're not willing to pay a Corvette shop to wrench for you (or you don't have a Corvette specialist nearby), I would avoid them.

 

Oh I do all my own work. I have a 1969 C3 so I know all about maintenance on them. My 69 is an original 427 car with a 3.08 rear. so Ironically it is better on the highway than my 1980 Automatic car. I' just looking for one that can cruise at 75 mph for 4 hours without much drama.

 

If the car you get is fairly sorted in terms of age-related stuff, any C4 should have zero issues doing that. You may get a little worried driving a 92-96 because the temp gauge will read higher than you'd expect from a typical car, but again, if it's properly sorted, that's totally normal. On the later LT1/LT4 cars, the fans don't even kick in until around 227F.

As to which C4 is best, I'm afraid I can only give you my incredibly biased opinion. If you acknowledge that I am biased and am speaking from only a single perspective, then I don't mind sharing that opinion. Just...you know...realize that I am completely biased.

84: Don't bother. One-off year with a bunch of one-off components and a crappy one-off engine with a one-off "computer" controlling what are essentially just carbs. Great if you want a rolling chassis to swap something awesome into on the cheap, crap if you just want to buy and drive. Manual transmission didn't even come with the Dana 44 rear end.
85: Don't bother. Yet another one-off year. The engine is at least better than the 84, but the computer controlling it is yet another one-year-only experiment that didn't go so well. At least the manual cars got the Dana 44.
86-88: Not interested. They're boring and dated. If being perpetually stuck in the 80s is your thing, go nuts, they're pretty cheap.
89: Manual cars got the ZF6 transmission for the first time, which is awesome. Otherwise this year is just as boring as the 86-88.
90-91: Same boring engine as the 85-89, but with newer computers and a redesigned interior. Still boring to me.
92: First year of the LT1 engine and Bosch 2U ABS/ASR. Decent car for what they typically go for, but a 93 is better.
93: Passive Keyless Entry added, which is nice. I wouldn't mind a 93 if it was cheap enough.
94: Arguably the best year for the automatic transmission, and one of the best years in terms of computer controls. If I were trying to get an automatic, this would be my preferred year. Also Admiral Blue is the best color for the C4 and this was the year it started.
95: Arguably the best year for the manual transmission LT1 due to getting J55 heavy duty brakes and the Bosch 5 ABS stock, and has the same great computer as the 94. If I were going for a manual, this would be my preferred year.
96: Arguably the best engine of all the base C4s as long as you get a manual transmission. All manual 96 cars came with the awesome LT4. They command quite a premium over the previous years, but are fantastic cars.

Of course, if the decision were between, say, a 1998 C5 and a 1996 C4, and the prices were around the same, I'd jump on the C5 instead. Less of a hassle, easier to get in and out of, cheaper and easier to maintain in general.

Anyway, that's my ridiculously biased take. I can go into more detail on all of those years but kept it brief here. Others will have very different opinions based on very different views of what makes their preferred year great.

 

My experience has been good so far. I would not hesitate to hop in mine and drive it cross country. Maybe I’m nuts? Drove it three hours home when I bought it (although in hindsight probably not the best move given tires/maintenance etc).

However I am fairly comfortable working on my cars and have shaken a lot of issues out it... Clutch hydraulics, headlight motor nylon bushings, ECM reflow, steering wheel tilt pin replacement, high beam switch adjustment, fixed cruise control, numerous other things I’m forgetting plus all of the other maintenance items and then a series of minor “upgrades”.

I haven’t found it hard to work on, and I dove in right away to start addressing. I think as long as you are willing and able to sort the car you can drive with confidence (especially the late models). I have a running list of items I have addressed or am addressing in the following thread over the last year:
https://www.corvetteforum.com/forums...re-begins.html

I understand that the C5 may be a better match for long distance cruising, while the C4 will be more raw. However, get a manual and drop it into 6th gear and a C4 will idle along at 75 mph and close to 30mpg all day.

Oh and I vote 93 is the best, not biased or anything. Constant fears of Opti or ECM failure with every twitch offset with a great gurgling and popping exhaust I’ve heard is unique to the 93 (maybe 92 as well)...batch fire on the first LT1s ends with more fuel in the exhaust and with a manual you can really make some fun noises. But maybe that’s just hearsay?! I like the 89s with ZF6 especially if you like that body style and dash (I was on the fence when I bought my 93). I think 92 or newer is best, with 94-96 even better.

 

Why not put an o/d trans in the c3? The 82 model had the 700r4.

 

FWIW I have taken several long road trips in my 89 convertible with no issues other than the lack of storage space. Most automatic C4s have great highway gears, not so much for the 1/4 mile. The upside is <2k cruising rpm and decent mpg as well.
As far as what year to buy that is a whole different can of worms that I will let others argue over.

 

THANK YOU so much. This has been great info Indeed! NoMake Wan that was really helpful to understand the differences in the C4 years!

 

Not worth the work or $$$ honestly. It's an L48 auto car. I'd convert to 5 speed if I wanted to put more $$$$ in her

 

Honestly, drive a bunch and buy what you like. 84s have their own weirdness. In regards to a building block it's probably the best long block of the bunch (same forged parts at the L82s iirc, basically an 010 block not exactly but a good block) but that's if you're planning on playing with it. 85 is the same long block with TPI. The best stock car is going to be a LT1 Era vehicle. I feel more comfortable in the early interior... fit better or just feel like I do. The early front suspension is better allegedly for track days but the late rear is better. There's a whole bunch of weirdness.

Realistically they're all about the same maintenance wise. I've had a lot more age related weirdness with TPI than CFI or LT1/4 but that's for sure a minority problem and I know it not to be the actual case. Parts availability is about the same. If I were looking for something to drive I'd be looking at a 94 personally. But just find one you like. There is nothing obscure about parts for any of them for the most part other than optis.

As far as a C5, get a later one so you don't have to worry about the BCM.

 

I have owned and ordered my 1993 torch red coup 6 speed since new! Drove off the dealer lot to Carisle the same day and drove every weekend to every show on the east coast. It always rode well got great gas mileage and a lot of first place trophys. Today it is garaged and looks like the day i bought it. Only problem is the OB1 system worth less. Codes mean nothing and you better have the Helms two part service manual to troubleshoot.One problem Opti and water pump and finding the correct one for your car! Other wise great car but finding a used one in the shape as mine is going to take time.

 

It's funny how peoples biases can be completely opposite. You make very valid points and they are accurate...but I completely and respectfully disagree with you

If you want reliability I would avoid the later LT1/LT4 cars. Yup I said it. The Opti spark is trash. If I were to leave it stock I would want an 84-91 with a small block and the HEI distributor. But let's be realistic. In today's day in age I think a lot of people buy a C4 with the intent of LS swapping the car. In that case if your swapping in a truck 5.3L with a 4L60e your best bet is to find an 84. The cars are cheap and all over the place. You can find a very nice car with low mileage for well under $10K.

I have an 84 with an LS6 and a 4L80e transmission. I wouldn't be afraid to drive it across the country if I had to.

 

The OBD1 system in the 1993 is certainly less sophisticated than the 1994, but not by a ton. In addition, I hope that when you wrote 'Helms' you actually meant to write 'GM Factory Service Manual'. I agree that if you do not know how to diagnose electronic systems and do not have a laptop, then trying to diagnose a complex sensor-related issue using only a paperclip is going to cause you nothing but endless suffering. But if you actually hook a computer up to the '93, you'll find that its OBD1 is actually quite extensive.

Finding the correct opti is very simple. 92-94 used the spline drive. 95-96 used the pin drive. Only buy an opti from Petris Enterprises, optisparksolutions on eBay, or in a pinch, Sac City Corvettes. Avoid optisparks from literally everywhere else. Problem solved!

I don't think we disagree at all, friend.

 

My 80 and 81 were more reliable than any of my C4's. Neither ran ran hot on a 100* summer day with ice cold AC One of them had a 500hp 408 sbc.

 

If you're asking between a C5 or C4 the general rule of thumb should be buy the newest car you can afford. Although personally I would only buy a C4 as I just flat out don't like the C5 body style.

C4's are reliable but as mention they are not exactly young cars now.

Compared to today's American cars, in the 90's GM along with other American car companies still hadn't quite figured out the reason Japan was crushing them was because of better quality overall.

The weather stripping on C4's flat out suck! There are spots on my C4 where it's pretty clear the paint was put on thin. I have the sports seats which were an upgrade, but compare to other sports cars the leather isn't that great. And the interior of a C4 always felt inferior to other similar sports cars...too much hard plastic.

Over the years though maintenance has been low, ball joints on the front and back, needed to replace the air conditioner clutch, weatherstripping replaced. Had the ETCBM computer module short out and replaced with a used one on ebay. PKE module died too, had to replace with an ebay used one, been fine since.

Water pump was replaced because of leaking and causing the serpentine belt to slip. Wiper switch now won't stop running the wipers when turned off, but I never drive the car if it's rain. Headlight module failed and needed to be replaced. My top is now starting to separate which is a PITA for me to fix as I don't own a garage.

Personally all of the above might be just attributed to the age of the car as the majority of those replacement parts have occurred in the last 10 years, but at the same time I've had a lot less headaches with my 89 RX-7 owning both brand new off the lot...although sold the RX-7 a couple of years ago because I did find myself preferring the Vette when going out for a drive!

Power train wise with the LT4 I do think GM hit that out of the park even in the decade of questionable quality from American car manufacturers.

 

The "optispark issue" is a boogeyman and way overblown. LT1s should not be avoided just for that reason. I've had two LT1 cars and they were/are both fantastic. If you get a non-vented distributor model (1992-1994), simply upgrade it with a vented unit. I heard that the 1995-1996 models were not only vented from the factory but the distributor shaft bearing was upgraded to a larger size for durability.

 

Always buy the newest car you can afford.

I've driven my 86 or 88 on long 10 hour drives with the AC on in the past, handles it fine. It wouldn't be quite as comfortable as the C5.

 

I was just looking at the Road & Track report and they said 125 mph in 3rd at 5,000 rpm and 125 mph in top at 3,500 rpm! That's good cruising. Car also got 21.5 mpg overall, which was pretty darn good in 1982.

Crossfire C3s and C4s have their good points, and have been reliable to quite a few people. Handy in 0-30 mph, which is what a lot of people experience.

 

Some don't believe the crossfire engines aren't reliable, they do had some quirks but the overall cfi system is nearly identical to the very reliable tbi systems that they put in millions of cars & trucks through 1995. As far as the long block, it was pretty good for the early 80s. 9 to 1 compression, forged pistons, heavy duty oil pump, aluminum water pump, and baffled oil pan.

 

For long distance drives the later Lt1 cars are the most comfortable and best riding.
Ive done all day drives in my 89 and 90z when I had them...but you need a tolerance for a stiffish ride.
Same as your older vettes get the nicest best maintained one you can find and youll enjoy it. Fixers....no way with a c4.

As much as I like the C4 Id grab a lower mi C5 for your useage just more of a cruiser type car overall.