1991 corvette


Asked by May 16, 2014 at 03:57 AM about the 1991 Chevrolet Corvette Coupe

Question type: Maintenance & Repair

I have a car that overheats when stuck in heavy traffic. Once I start moving the temp drops
. The fans comes on when the car is near the red zone. Could it be the water pump, or
bad relays. the thermostic is out.

4 Answers


Don't be surprised, it's a general problem on most of the C4 Corvettes. I have a 94 and it's been the same problem. Radiator flush, themostat, The thermostat is 180 from the factory and should be fine. One issue is the system gets air bound because of the radiator location. When the stat is closed no flow, I drilles two 1/16 holes in the stat opposite each other, that took care of the airbound condition.Still temp in the 220-240 range. ATo me thsts scary but normal. The last thing I have done was a little expensive.(285.00) Got a computer program for my laptop and can adjust the temp when the secondary fan comes on, it was 195 I dropped it to 185 seems to woks so far runs 205 the highest. Thermostat out is not good, it messes with the on board computer, engine temp needs at least 200 . When you turn on the AC the left fan will come on and stay on until you turn it off .If the fans work the relays will not change anthing. Good Luck

1 out of 1 people think this is helpful.

You could replace the temp sensor on the block to one with a lower actuating temperature, or have a fan override switch installed in the cabin so the driver can manually activate the fan when in overheat situations. These items and more are available at www.corvettecentral.com


Continuing issues last resort ---machine flush of the radiator mine sat for over three years hopeful sediment is blocking proper flow . This doesn't work as long as it doesn't peg the guage I'm driving.. had teh new sender from Eckler's alternator ac compressor off to access cyliner head loction. Hex head core plug has to be remover after 23 years lots of luvk on that one. Sent it back


I had the same problem. Put a temp sensor to have the secondary fan turn on at a lower temp and a lower opening thermostat. Finally installed a 2 row aluminum radiator and man it does not overheat at all. But. I cleaned the old radiator really well to sell it on Craigslist. When I sprayed the fins out, a ton of fresh cut grass came out. My bet is that this was my issue all along. I am happy with the new radiator though.

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