Thermostat Problems?
Thread Starter
5th Gear
Joined: Jul 2008
Posts: 5
Likes: 0
Thermostat Problems?
Any ideas! We have replaced the thermostat in our 60 vette 3 times due to running hot (stock temp gauge reading 220). Finally out of desperation I cored out the center of the thermostat and that worked for a while. Mechanic said it wasnt a good idea so he put in a new bypass thermostat and a flex-a-lite electric fan. But the second time I took the car out the gauge pegged at 220 and anti freeze shooting out of overflow hose I think. The upper radiator hose was soft and cold.
So now I bought infrared measurement tool and see whats going on. the front of engine manifold temp was 230 while the back was closer to normal and the upper radiator hose was cold which I guess means the thermostat didnt open. In time the thermostat opened the electric fan kicks on but the engine only barely cools down.
Im new to the forum and would appreciate any advice or suggestions that can be offered. Thanks guys!
So now I bought infrared measurement tool and see whats going on. the front of engine manifold temp was 230 while the back was closer to normal and the upper radiator hose was cold which I guess means the thermostat didnt open. In time the thermostat opened the electric fan kicks on but the engine only barely cools down.
Im new to the forum and would appreciate any advice or suggestions that can be offered. Thanks guys!
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
stop replacing the t-stat, it has nothing to do with how hot your motor runs, the t-stat only controls the minimum operating temp the motor will run at, not how hot it will get. Your problem is elsewhere. It's possible to get a bad t-stat at the store but 3 in a row being bad has awfully high odds against it.
If your mechanic is trying to "fix" the problem by adding items like electric fans rather than finding and fixing the real issue causing your cooling issues it's time for a new mechanic.
1. first of all, WHEN does the overheating occur, during idle / slow driving or highway driving?
2. What kind of radiator is in the car?
3. is your fan clutch working properly?
4. do you have the correct lower radiator hose with the internal spring in it?
5. what is your timing set at and is your vacuum advance system working and hooked up to full manifold vacuum?
6. waterpump working correctly?
if the intake manifold has such a difference of temp from the front of the motor to the rear, have you had it off the motor at all and replaced the gaskets with incorrect ones that could possibly be blocking the coolant passages in the heads?
If your mechanic is trying to "fix" the problem by adding items like electric fans rather than finding and fixing the real issue causing your cooling issues it's time for a new mechanic.
1. first of all, WHEN does the overheating occur, during idle / slow driving or highway driving?
2. What kind of radiator is in the car?
3. is your fan clutch working properly?
4. do you have the correct lower radiator hose with the internal spring in it?
5. what is your timing set at and is your vacuum advance system working and hooked up to full manifold vacuum?
6. waterpump working correctly?
if the intake manifold has such a difference of temp from the front of the motor to the rear, have you had it off the motor at all and replaced the gaskets with incorrect ones that could possibly be blocking the coolant passages in the heads?
Le Mans Master
Joined: Mar 2005
Posts: 7,631
Likes: 11
From: Rocklin California
Any ideas! We have replaced the thermostat in our 60 vette 3 times due to running hot (stock temp gauge reading 220). Finally out of desperation I cored out the center of the thermostat and that worked for a while. Mechanic said it wasnt a good idea so he put in a new bypass thermostat and a flex-a-lite electric fan. But the second time I took the car out the gauge pegged at 220 and anti freeze shooting out of overflow hose I think. The upper radiator hose was soft and cold.
So now I bought infrared measurement tool and see whats going on. the front of engine manifold temp was 230 while the back was closer to normal and the upper radiator hose was cold which I guess means the thermostat didnt open. In time the thermostat opened the electric fan kicks on but the engine only barely cools down.
Im new to the forum and would appreciate any advice or suggestions that can be offered. Thanks guys!
So now I bought infrared measurement tool and see whats going on. the front of engine manifold temp was 230 while the back was closer to normal and the upper radiator hose was cold which I guess means the thermostat didnt open. In time the thermostat opened the electric fan kicks on but the engine only barely cools down.
Im new to the forum and would appreciate any advice or suggestions that can be offered. Thanks guys!
Le Mans Master
Joined: Feb 2003
Posts: 6,369
Likes: 73
From: The line waiting to see Santa Claus stretched all the way back to Terre Haute, and I was at the end, Indiana
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18
I was having trouble with my '64 365hp running hot intermitently, especially at idle or low speed. I replaced radiator and overflow caps, thermostat, and flushed the radiator. It still ran hot...sometimes. 
Apparently, the fan clutch was acting up. It would be okay one time, then loose the next. I replaced it and now it runs fine.
Apparently, the fan clutch was acting up. It would be okay one time, then loose the next. I replaced it and now it runs fine.
Instructor
Joined: Aug 2002
Posts: 159
Likes: 0
From: Montague NJ
I also had overheating problems when stuck in traffic on hot day. Tried everything on 540 motor with brand new BeCool rad but nothing worked until I used BB 454 AC fan clutch and 7 blade AC fan. Now car can idle all day in 100 degrees and temp barely opens thermostat. I love it when a plan comes together. Thank you to Tom McCabe for info.
Regards,
Gerry
Regards,
Gerry
