I will be purchasing a c4 within about a month, either 85 or 86 with a 4+3. I currently live in Toronto, Canada and have seen the brutal effects of a rusted undercarriage and/or frame rails. I'm definitely planning on buying a c4 in the US but can't decide whether it's risky buying from any northern states because of the snow/salt and the possibility of me going all the way down there to see a rusted out car. I will also be swapping a modded 383 into it within a year, so that's why i need the car to have a solid platform and be structurally sound.

My main question is if vettes have a tendency to get rusted out from underneath (obviously not the body) in a snow-ridden city. Afterall, even if the owner doesn't "drive" it in the winter, it could still have seen salt and have a rusted frame. I doubt i'd want to get into pricing for a local shop to replace the frame or repair segments...

 

Greetings,
The frames are made of steel / low alloy and I've never heard of one rusting out. I'm on my second C4 (1989 & 1986) and the frames have always looked like new.
Having driven the 89 occasionally in the winter, you'll soon find that they are absolutely terrible in the snow and you'll soon try to avoid it at all costs, which should greatly diminish the ill effects of salt.
A cursory visual of the frame should tell you what shape it is in. The first thing I would do when searching for a used Vette is to look for a low mileage example.....my last one was owned by an old guy and only had 24,000 miles and looked like new. Try to find one where the service records are available and for goodness sake get a mechanic to give it a once over before you buy. Don't buy it alone, bring a knowledgable buddy and take your time. It's easy to get excited and miss a few important steps.
Try the AutoTrader website in both Canada and the US and look for that low mileage creampuff; they're out there
Good Luck !
Ken - Windsor, Ontario

 

I believe they were galvanized. Gordon Killebrew said in one of the classes I attended that the C4 frame has not had rust problems. I live in Michigan and rarely see any year Corvette on the roads beginning with the first heavy snow and ending with the first gully washer rainstorm in the spring.

 

If exposed enough times to salted streets, sure it's going to rust. How much damage from rust is determined by how frequently it was exposed to those conditions and over how many years, just like in Canada.

Buying long distance, sight unseen, and relying on the honesty of the seller is risky. You might be able to get a forum member near the Vette you are interested in and ask that they inspect it for you. If you're looking for a guarantee I doubt you'll find one. You might have more peace of mind buying one in Canada where you can inspect it personally. Check the classified on this forum, there might be something there that meets your expectations and may be know by other members who can vouch for it's condition.

 

noobs helping noobs

I have to agree. These C4's are nothing like the C3's with rusted bird cages et al. Driving a vette in the snow, although very doable, is a suicide mission that few undertake. We have a few members that drive year round, but like most of us they are fanatics and keep everything nice with religious cleaning. I would bet a nut that you would be extremely hard pressed to find a C4 with a rusted frame, the parts you can see anyway.

Someone will correct me if I am wrong but my understanding of the following is slim. The C4 looks like a unibody, but it isn't. The frame is integral to the car, and you would have to literally cut the car from the frame to be able to see it. The parts you can see might be scaley with paint flaking off in spots, but it's nothing to worry about.

I have a cavalier, a 97 owned since new and driven year round, that mechanics actually compliment me on because the underside is cherry. I am at the car wash once a week in the winter time and take good care of it though. My point is, don't worry about the structural integrity of the frame unless you have some reason to believe the car was in an accident. Given most of us drive different cars in the snow, and usually wait until the first good rain to wash the salt off the roads before we drive, you'll be fine.

 

Ive seen rust on them before...especially in the rear.That due to excess salt sitting in places it cant wash out.The frames are very good at resisting rust but I do not think you would get any more than surface rust.Should not have any serious frame corrosion.

But you really need to inspect way up inside there for any possible problems.A quick look under isnt wall it takes.

That being said,the fuel lines,gas tank,sway bar and etc easily get rust on them.I replaced the gas tank and fuel lines in my 86 because of rust.
The back fuel lines were so corroded with rust,they were inside above the wheel well frame area,I was wondering when the next bump would bust a hole in the lines.These are the critical areas to inspecting any and early C4's to see what its going to cost you IF those areas need repairs.

The car had been through some snowstorms in the NE area and the road salt was the probably the main cause.

 

Check under the battery too. Any excess acid will eat right through to the bare metal.

 

My '85 has been used year round now for at least as long as I've had it- 6 winters counting This one. Probably previous owners had it out in the salt at least Once in a while... Snow, salt and whatever. (Driving a vette in the snow isn't That bad - try some decent winter rubber on it This subject has been covered in depth elsewhere..). keeping an eye underneath for the effects of salt shows that it is starting to take a toll - the brake and fuel lines in the back are beginning to get rusty (time to oil it up - it isn't a show car, after all). Maybe I'll replace with stainless lines when the time comes and eliminate the issue. I'm somewhat more concerned about the aluminum rear subframe - it's showing a surface oxidation, at least I Hope it's just a surface oxidation, that doesn't look healthy. I haven't found a good way to stop/prevent it - yet - either. The aluminum Suspension pieces, incl. the diff, all seem to be immune. The radio antenna looks very exposed - but so far it's holding up OK. The parking brakes ('85 is internal expanding drum type) seem well protected and are also holding up well. Other areas to watch: The floors under the seats are sheet metal - and will also rust from the Inside (under the carpet). The metal guards at the leading edges of the footwells should be protected - I undercoat over them. The gas tank wouldn't leak even if the metal skin did rust through - the plastic bladder would still be intact. Since gas tanks normally rust through from the Inside (water in the fuel) anyhow this probably isn't ever going to be a problem on a C4. The Exhaust is what it is - probably the most suseptable stuff under there.
With the possible exception of the rear aluminum sub frame the rest of the "structural" stuff - the main frame itself, looks Really good - not even showing any Surface rust except for the cross bulkhead behind the seats - right at the bottom where it's the most exposed - and not Bad even there - a little paint in the spring will solve That problem. It appears that the car will survive it - and continue to get used (snow, salt or whatever) for many more winters to come... Use it - it's what it's for!

 

Great info guys, i'm a little more reassured now in buying a vette from a snowtown.

much appreciated,
Dave

 

just put it on a lift and give it a good look. Put you finger and light any where you can. Depends how the owner treated it. I have a rust phobia. POR15 works great on top of any rust. It seals it for good with minimal prep. You just brush in on and done.

 

.................Ya mean like this?This is the windshield frame in my 84 and I live in Ca.

 

I have an 88 4+3 that will be for sale, Actually it can be for sale right now! Car has 121k or 75000 miles on it. NO RUST! Car has been taking care of........If your serious and want a clean car let me know. I am just north of T.O. up in Barrie. I too was going to do a 383, So if I sell the car, I have alot of performance parts that I will have to unload like a brand new set of TRICKFLOW HEADS, and a MINIRAM II intake system with fuel rails. You can pm me for further info. I have pics, and vids of my car. No shortcuts!

 

.............The windshield frame is also prone to rust.This is the windshield frame in my 84.Ive had this car since 87 and as far as I can tell the windshield has never been replaced until now,and I live in Ca.