Overheating LT1 Engine

sounds like the fan relay to me. dont know where it is though. try tracing the wiring back from fans themselves and it should lead you to it. should be able to use a voltmeter to determine if the relay is the issue or if its somthing else.

Thank you Chase for your advice. I did try to try to trace the wiring, but it goes in to a larger group of wires and now I have to try and figure out which is which and where the relay is.

There should be a temp sensor in the block which tells the fan when to go on, sounds like that's dead. You may want to invest in a 'real' shop manual by Helms, cost over $100 but well worth if you plan on doing any more than casual repairs to the car, they can be found for less on eBay. But my guess is the temp sensor, easy to check if you have the manual to follow the troubleshooting flow charts.

I took the car to a shop yesterday they checked the relays they were ok and the mechanic said both fans were running, could not find a problem, words we have all heard before. I picked up the car and drove it for a have hour the temp went up to 235, I got home opened hood both fans were running. I turned off engine and coolant was blowing out of overflow bottle I started engine being curious and temp rose to 275. Drove car back to shop and he said he does not know whats causing problem take it to a corvette specialty shop, can't get that appointment until June 28. Checked thermostat that opens and closes, fans are running, but it overheats and coolant blows out of overflow. I am confused, could there be a blockage, would a system flush possibly correct ? Has this happened to anyone else ? Suggestions are welcomed please.

Thank you Joe for your info. I did post another reply after this one explainng some more info.

Try a flush. Might have some air trapped in the system? If that doesn't work your water pump may be shot.

Thank You Chase for the info I will have that done this weekend and hope for the best.

Took corvette to have a system flush they tried and then after a hour said it could not be done there was a blockage and no heat comes out when you turn heater on. Try a new thermostat this is usually the problem they said. I replaced thermostat still had same problem no heat, overheated coolant bellows out the overflow bottle. Then someone said unhook hoses to heater core and flush out with garden hose, I did this for 3 hours until I saw no more or very little corrosion or blockage. I filled with coolant drove for an hour temp rose to 215 turned on heat still no heat cool air only got home pulled in driveway let it idle opened hood coolant fans were working, no coolant blew out overflow, but turned heat on still no heat and temp rose to 234 degrees. I don't know, maybe its the heater core, please any/all suggestions and info are welcomed. I made an appointment at a local corvette repair shop and the earliet they could give me is June 28, 2011 I hope I can hold out that long. Thanks everyone.

You should be able to rig up something to bypass the heater core easily, that's one way to find out if it the core. You won't have any heat but it's the middle of summer so, no biggie.

Thanks Joe, I guess I could just unhook the hose from the core that goes to the coolant fill tank and hook the other hose that goes from the core to the engine to the fill tank.

or if you can get to where the hoses connect to the core on the firewall just hook 'em together there...

I will see if I can find a piece of hose or pvc to clamp them together. Thanks Joe.

mine overheats if my climate control is off otherwise it seems okay???

Sounds like one of the final stages of elimination for sure. Lots of money and frustration and still no answers? With fans running, water pump and stat working the list possibilities is coming to a close.

Fellows, I had just gotten a 1996 LT1 corvette. Noticed it ran around 215-225 while driving and higher while just sitting in traffic. I replaced the radiator, hoses , censor but mechanic said it was still running high unless the defrost or a/c was on. I then called a corvette mechanic , he stated that these cars ran at a higher temp than the others. He said it was normal. I still don't like it though. Having a hard time getting use to it.