I know this is probably a frequently asked question...

But... I have a 1989 that I frequently race, NCCC high speed and low speed AutoX, drag racing and some track days on road courses.

As most people know, C4's run hot. Keeping them running cool even in normal driving is a problem. Keeping one cool pushing it hard is an exercise in frustration. I've already done a few things... I bought a Z51 oil cooler, which has been pretty effective at keeping the oil temps under control. Before that I was seeing 260+ on the oil, now it rarely goes over 240. The fan not coming on until 232 is just way too late, so I also had a fan override installed for use when racing which helps on the coolant temp, but has unfortunately caused my fan to wear out. It is making a lot of noise, is wobbly and doesn't seem to be doing an adequate job. I have a used fan located I can put in, but I also have a dual fan setup from a 1993 I might try to fit if that might be a better choice. I also have a Z51 "pusher" fan which I bought off eBay that I was going to install. I'm not sure if the original style single large main fan plus the Z51 pusher is a better choice or the 1993 dual smaller fans... Or the 1993 fans + the Z51 pusher. And do I want to consider different sensors or combinations of manual overrides to wire this thing up. Anyway, looking for info an opinions on what way to go here.

Now -- the main reason for this post... Radiators... While my original radiator seems to be OK, it doesn't leak nor does it appear to be full of sediment and blocked or anything... But it just seems inadequate. I'm wondering what the best, or at least a really good aftermarket radiator would be? Something that will fit without a lot of modifications but offer better cooling. DeWitts? Griffin? Any others I should look at? Where's the best place to get something like that?

 

I have been looking at the DeWitts,for my worked 85. it worked wonders on my 71. It also fit well.

 

Negative. Not if the cooling system has been properly maintained. The cooling system was engineered to be way better than good enough in extreme temps that most of us don't see. I've Auto-x'd, Tracked, Drag tracked my car for years and it's had no issues.....in fact in one particular auto=x event, temps were over 100*F. I simply turned on the AC the entire time the car was running to force the fans on...it never went above 210*F....and a bonus is that I was cool too!




My stock radiator worked better than good enough, for years...decades. I now have a Tom DeWitts radiator...but not b/c "C4's run hot"...b/c mine didn't. My radiator side tank cracked after 20-something years, so that was the end of that radiator. Not wanting another cracked side tank, I bought a fabricated aluminum radiator. It works....too.

 

The ebay fabricated aluminum radiators aren't as nice as a DeWitts one but for the price they're unbeatable. They're a stock equivalent, but they do squeeze in a few more rows so there's a wee bit more performance to be had, I believe it was somewhere in the 8% range of greater tube density the core is also a tiny bit thicker, but that doesn't necessarily mean more performance.
My 85 had an annoying leak that I could never find, and rather than mess around with it I said screw it went with one of the ebay ones. The build quality was pretty surprising, the only thing I'm not using from the kit is the radiator cap, the one they included was cheap and flimsy and I had no faith in it.

 

I have a Dewitts in my 88, 383 engine .. In front of that i have 2 B&M stacked plate coolers, 1 for the engine oil, 1 for the tranny. I used the stock fans (1 pusher 1 puller - my car had that option). Each fan has its own temp switch in the intake, i believe main comes on at 185, 2nd comes on at 195. Running the car hard my temp stays at 190ish, tranny has not gotten above 160, and engine oil stays around 200. Even when i shut the car down the fans are not on.

The dewitts fit perfectly, just have to trim the rubber blocks a little. Glad i went that route. Expensive, but worth it. Just my .02

 

Dewitts++++

 

Eastwood is now selling radiators that are designed to solve Hot running issues. If you used one with the cool running Corvette it would stay cool. The prices are not too bad either. I have a BeCool Radiator in my C3 and a stock replacement in my C4. And my C4 never had any problems with Higher temperatures as like FostersPerformance I have the B4P Auxiallary Fan on my C4. I have it connected to a switch that controls the Auxiallary fan's power so during the warmer months I leave it on all the time.

I spoke to Tom at Dewitts and he was sure that he could help me but the prices was almost three times what other radiators would have cost me. I like the quality and detail they do but at that price I might have to pass. It was for a Hot running High Compression 427 in my C3. They clearly have very valuable knowledge of building great radiators and if I was able to afford one I would probably buy from Dewitts. I am not going to buy a Chinese made unit at ANY price!

 

Whut??



No C4 should.
Change the coolant.
Keep the radiator clear of debris
Have an air dam, intact.
Verify that the fans are working right

Car will keep itself cool.

 

When the C4 Corvette was going through "testing" they ran them in some horrendous conditions to verify the design. They made them run in conditions similar to Death valley (at it's very worst) and "Extreme Cold" weather as well (at least to me in Virginia). The factory Stock Corvette is Fine the way it was designed IF it is maintained as you so kindly pointed out to us. It is up to us to keep them running the right way.

I change the Coolant along with the Radiator Cap and frequently a Thermostat as well. I use an aftermarket Modified Thermostat with the holes drilled in it. The cooling system is really important to keep working properly. As mentioned keeping the Rubber Air Dam intact is really important as it keeps the air moving through the radiator versus under the Car. The Pusher Fan on the B4P Aux. Cooling fan seemed like a "last minute" idea. I had not seen Electric Fans on Both sides of the Radiator.

Frequently people ignore their Radiator Overflow Tank as they work "reliably" when they are in good shape. If the Overflow is not working then you are most likely sucking air into your Radiator every time it cools down. The coolant is supposed to Expand as it gets Hot and then go to the overflow. Then when the car is shut off and starts to cool off the Fluid in the overflow is then drawn back into the Radiator. If the Overflow Hose is broken then you will be pulling air back into the radiator when the engine cools down. This idea is fairly simple but I have seen so many that are not being used or maintained on Corvettes out there. That air is a bad thing to have in the radiator.

Electric Fans should be inspected every so often to be sure that your Relays or other Wires are not melting from loose connections in their wiring. An Electric Fan not working properly is not a good thing either, listen to them and feel the blades to make sure they are not loose.

Lets keep our Corvettes on the road where they belong with a bit of preventative maintenance, agreed?

 

100%

The vast majority of the "issues" we see on here...and especially "C4's run hot" are due to poor maintenance.

 

Running the AC is not allowed in any of the AutoX or drags around here. They don't want any condensation dripping on the track or in the staging area. Getting caught with AC on can result in DQ. I often run the heater and blower fan on full, as that helps a little, but it makes it pretty uncomfortable in the car.

I live in Central Texas -- 100+ degrees outdoors is common more than half the year here, not the exception.

FWIW, water pump, thermostat and hoses are new. The coolant is changed regularly and I keep it full and the fan relay has been replaced recently. The fan failure is a recent thing I think because I've had to force it on so much.

Radiator is not full of debris and does not appear to be plugged with calcification. So I don't think it is a maintenance problem, because I've done all the basics already.

I forgot to mention... car is an automatic, but I am running a separate transmission cooler, so that is not putting extra temp into the radiator like it was originally -- still the car runs too hot. Also I have added the "big mouth" cooling scoop on the front of the car. It helps compared to the stock rubber, but only when the car is moving. When it is sitting in staging the car still gets too hot.

The stock radiator and fan, at least with the factory turn-on temp is just not adequate on these cars to keep it running under 220 degrees for water when the car is not moving unless the fan is forced on all the time. My C3 never runs that hot even when pushed hard.

Anyway, it is sounding like DeWitt's may be worth the $$$, but I will check out the Eastwood ones too, they seem like a good company, I've bought powder coat and other stuff from them. I'm going to replace the fan that is failing and install the Z51 pusher fan I have on a manual switch to see if that helps. If it still isn't staying under 220, I'm going to buy an upgraded radiator.

 

Do they cancel auto x's for rain, too, where you live??

I bet you could run the AC at the drag track anywhere but the burnout box onward. If not, find a new track.


As for the rest....IDK. I have a C4. We have to temps too...as I explained. My car doesn't have any kind of "C4 runs hot" problems. I'm sure that a DeWitts radiator will help but it sounds more like an air flow issue to me. I'd probably upgrade the fan(s) first.

 

I went with a Griffin 1-25241-X in my 84. The quality is very good and it's made in the USA. The price was only $185 and it's probably the thickest aftermarket radiator option that will fit a C4. This thing is 3" thick. It's not drop in however. You need to trim the upper and lower covers just a little. I also made new rubber feet for it to sit on. But all in all not bad at all. I had it done in a few hours. With this on a hot day my temps are around 190 in traffic. I have a 180 thermostat and I'm still running the stock fan.

 

I bet you are wrong here. We have humidity in Texas. The a/c will drip water for 10 minutes after you turn it off. I've seen many car's sent to the pits at the track i frequent. Dripping condensate

 

Maybe. But we run auto x's in the rain....Did the same in the New England Region too. Same goes for track days. Track is still open in the rain. So I don't know that an AC condenser can compete with rain fall, or is going to stop an auto-x or a track day. I made it through an event w/no drama, running my AC. And I've run Auto-x's and track days in the rain.

ANYWAY....you could take that advice (run the AC to force the fans on), modify it slightly and run your fans differently, just like running the AC does....but w/o running the AC. You know?

 

This... if you are in staging and dripping anything you can get DQ'd at an AutoX, and pretty much every drag strip or road course around here has the same rules about no AC.

 

Rain shuts drags down. We run AutoX in the rain also. And sure, you could probably get away with running AC on a rainy day. A dry day people will notice. DQ. It is hot and dry most of the year here. 250+ sunny days a year.

 

Yep. Note that I didn't mention that I'd drag raced in the rain. However, I HAVE run the AC on the return road, in the pits and in the staging lanes. No massive wrecks yet!

I live in UT, as you can see under my screen name. Dry and sunny here too...doesn't get much drier than here. No issues auto-x'ing with AC on and never been DQ'd. No once notices or cares. And why should they? A few drops of water spread across a 60 course is functionally MEANINGLESS. That's called, "Worryin' about **** that ain't worth worryin' about". No one cared when I raced back in the New England region either, some 30 years ago....but something that I learned from running auto-x there and then out here is that different regions have greatly differing, ah...."cultures" though, so maybe your region has a bunch of busy-body sticklers? IDK....that would suck and be irritating.

Shouldn't need AC on a road course as you're going faster than fast enough for good air flow.

 

STILL, All this BS about water droplets on asphalt is also, "Nit-picking **** that ain't worth nit-picking". If you can get past what *I* do at tracks/events, then a useful take-away for you could be:
...and thow a manual switch in the car....or something like that. That was the "bigger picture" point; run the fans and the car doesn't get hot at low speeds.












.

 

can you not just pull the clutch coil plug and throw on the AC and that'll trick the fans on without having the ac actually be on/running? Or even just the fuse?