hello everyone. i have a 1990 (my first) that is running warm. i took the vette into the dealer and explained the symptoms that the engine heats up while idling. 500 hundred bucks later after diagnosing (the dealer) and replacing the thermostat i'm faced with the same problem. they say that vettes run warm and this one idles @ 215F. and should be fine??? is this temp normal??? Thanks!

 

Hi- Sounds a tad hot to me. You probably have a bunch of debris built up behind the radiator. Leaves and other types of crap floating around out there on the road get sucked up in there and after time lodge in behind the radiator blocking the flow thus causing it not to to cool as it should...........

 

Shoulda come here first!!!! That'll learn ya!
You need to get used to higher coolant temps because C4's were designed with a radiator sized to get rid of heat fast enough to maintain 180-195 (depending on year) coolant temps when you are moving over 35 mph. Idling, no air is passing through the radiator and the temperature will continue to rise until it gets to 228F and the ECM will turn on the main fan. Temp will drop to about 210F and the fan will go off. Usually in traffic, you never sit there long enough to get to 228. At least it has never happened to me and we get 90 F temps in the summer here. When you get underway, your coolant temp will drop to the opening temp of your STOCK thermostat (195 early C4's, 180 later C4's). In my 87 with the stock water pump, I used to see 220 at long stoplights in the summer. I replaced my leaking pump with a Stewart pump which has 40% more flow than stock and now I see 205 F and it cools down to 195 much faster than with the stock waterpump when I get underway. Be aware that 228 F is not harmful to your engine, but it is above your experience with older cars that would stay at 180 no matter what. It takes some getting used to. If you search around you will find some BIG discussions about installing 160 F thermostats. It isn't the thermostat that determines the operating temp, it is the size of the radiator! In very cold weather, the radiator has much higher heat ridding capacity (capacity is proportional to the difference temp between coolant and outside air) and it could be possible with a 160 stat to run 160 F. In the summer, the 160 stat will be wide open and you will be at the mercy of the radiator performance and you will see temps near 195 depending on the air temp. Now stand back and watch another battle over 160 thermostats!!!!!!!!!!!!!!!!!!!!!!!
Oh yeah, GM says to shut off the engine if the coolant temp gets to 260 F (I've never seen it) and let the engine cool down. I am lazy and I shoot a stream of water from my garden hose backwards (hold the fan blade) through my radiator to clean it out. C4's collect a lot of road debris in the front of the radiator (a/c condenser too!).

 

Do a search on "overheating"you will find alot of info.This question pops up every week.What exactly did the dealer do for $500? Vettes will always run hot when idling -your temp is normal 215.The fans kick on at about 228 dg.If you put the ac on the fans turn on and will lower the temp.Some Vette owners modify the cooling system but that is another issue and dont want to start a crazy 160 vs 180 dg thread again.I would make sure the fans work.turn on the a/c you should see them work.The vette is known to suck up debris(leaves,candy wrappers,sand etc) and clog some of the radiator.This should be looked at.I would hope that the dealer checked this out and also changed your anti freeze.What is your cruising temps-mine are about 197-201 but I have an LT1 engine.Enjoy your car and stay away from the dealers-You have more experienced people that are familar with 17 year old cars on this forum than at your local dealership.

 

Hi- My '88 started running a little hotter than normal (overall avg. running temp of 210). I couldn't figure out what it was. After trying new thermostat, temp sensor etc. etc. A local Vette guru told me to check for debris around the bottom of the radiator. I took the whole thing out and there was about a pound or more of crap under there. Cleaned it out and the car immediatly ran at normal temps again. Another one of those it's a Corvette "gotcha's"............

 

I used a air compressor.

 

Welcome to the forum, I have a '90 vert, my experience is Dealership=Stealership, I have learned to do it yourself, or find a Corvette specialty shop to complete repairs, which are too complicated. With that said my '90 has always ran hot, then I moved to Arizona to add to the problem.
As stated above throughly check your radiator, ensure all debris is removed between the radiator and the condenser. Do you have the stock radiator in your car, if so have you flushed the system to clean gunk from inside the radiator? Also look into burping the system.

Use the search function of the forum (advanced) set back and learn from other C-4 experiences.

Try this link
http://forums.corvetteforum.com/sear...archid=5719845

Hope this helps

 

When I lived in Dallas, David at the Corvette Shop installed a fan switch/relay that turns on both my fans at 200 degrees. You might consider this because of the peace-o-mind it will give you. I no longer worry about traffic congestion or long stop lights. At 200 degrees, the fans kick on -- at 185 they turn off. Ahhhh Yesssss.

 

You could install a HP radiator, such as Dewitts. They make an excellent model for your car. Don't go to a 160 thermo. You don't need it and it may have deleterious effects. I'm betting that what others have said here is right on the money - you've got all kinds of junk blocking the air flow. Clean it out and I bet you'll be good to go.

 

Thats a good idea......

 

That's exactly why you don't go to dealers--$500 later and they tell you that's how it's supposted to work. My son just went through that with his Mitsu, $400 in diagnosing and they tell him it's his alarm that won't let it start; alarm gets removed, still won't start; goes to another shop and literally in 30 minutes, problem is found and repaired. Cost to repair--$19 (bad relay).

 

I did teh Hypertech 170 switch, in teh driver's side head...to 6 minutes, start to finish and now I don't
go over 210 (in Arizona summer).

 

My 86 was overheating up to 260F and I had put a new radiator in it. CentralCoaster took a look at it and cleaned out all the junk in front of the radiator and temps returned back down to 180F. He also recommended I install a Big Mouth Air Intake which I did. He also installed an auxillary fan and wired up a switch inside my car so I can turn the fans on at anytime. I usually turn them on whenever the temps hit 185F. Thanks a lot Kevin!