'91 Overheating problems, any advice?
Thread Starter
Team Owner
Joined: Feb 1999
Posts: 34,454
Likes: 665
From: Republic of Texas
'91 Overheating problems, any advice?
Last year I thought I had solved my cooling issues but I guess not. So far I replaced the water pump, wired both fans to run all the time, switched to a 160 degree thermostat, had the heads checked for cracks(had a valve job while they were off) and had my stock radiator rotted out. On a 90 degree day the car slowing creeps up in temp and even on the interstate will reach 240-250 degrees. As soon as I turn on the heater the temp drops to 230 degrees or so. I'm thinking because of this it's my radiator. But you would think w/ only 100K miles and having it rotted out it should suffice, no??
Any ideas what it could be?
Any ideas what it could be?
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Re: '91 Overheating problems, any advice? (Corey 68)
Corey 68, all that is required for engine cooling is: (1) air flow (vehicle speed or fans) through the heat exchanger (radiator) and: (2) coolant flow (water pump, tstat, radiator). Excessive heat is caused by a failure or fault in one, or all.
Assuming your tstat is opening fully, and the pump is circulating the coolant without air pockets, your focus should be on a restriction in the radiator. An exhaust head gasket leak would create more serious problems. Your fans should only be "on" when the vette is not at "speed". There is no harm done having the fans "on" at all times. It is just an unnecessary use of an electric motor and bearings.
Rodding a radiator is 100 year-old technology. Either rebuild, or replace your radiator, if all other components are are working properly.
By turning on the heater you are just adding another heat exchanger (heater) to the cooling system that aids in transferring heat from the coolant. The heater is just a radiator with the air flow directed to the inside compartment.
You might seek an opinion on a radiatior replacement.
[Modified by Oldman, 1:44 PM 8/3/2003]
Assuming your tstat is opening fully, and the pump is circulating the coolant without air pockets, your focus should be on a restriction in the radiator. An exhaust head gasket leak would create more serious problems. Your fans should only be "on" when the vette is not at "speed". There is no harm done having the fans "on" at all times. It is just an unnecessary use of an electric motor and bearings.
Rodding a radiator is 100 year-old technology. Either rebuild, or replace your radiator, if all other components are are working properly.
By turning on the heater you are just adding another heat exchanger (heater) to the cooling system that aids in transferring heat from the coolant. The heater is just a radiator with the air flow directed to the inside compartment.
You might seek an opinion on a radiatior replacement.
[Modified by Oldman, 1:44 PM 8/3/2003]
5th Gear
Joined: Jul 2003
Posts: 5
Likes: 0
From: Wayne NJ
Re: '91 Overheating problems, any advice? (Corey 68)
Corey, my setup is like yours and I was experiencing the same problems> I changed the radiator (got the replacement from Eckler's for 199.99). I installed it in about three hours (taking my time - the hardest thing was getting the lower transmission line since I did not jack the car up). Bottom line since I replaced it is that I never go above 185.
