overheating 71
Thread Starter
1st Gear
Joined: Sep 2004
Posts: 1
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overheating 71
help!, i have been trying to chase down my overheating probllem all summer.my vette runs realitively cool in town but overheats on the highway. i have found what i think may be the source or part of the problem. with the mark on the harmonic balancer on zero on the compression stroke the rotor button is pointing at the correct position, however the wires on the distributor cap are off one position clockwise. i did not build this motor so i am not sure of its internals. i also have a 73 vette that i have compared to the 71 which is how a found the difference in the distributor cap wiring. the motor has plenty of power but runs really hot on the interstate. HELP!!!
Melting Slicks
Joined: May 1999
Posts: 2,897
Likes: 0
From: Moon Township PA
Your car won't run with all of the wires off by one post unless the distributor was installed a bit off and they compensated for it by adjusting the wires. If you are having overheating problems on the highway I would think it could be an original, but crudded up, radiator; poor water circulation due to a worn pump; a weak lower radiator hose that is collapsing due to a missing internal spring.
My 66 had identical problems that were only solved when I replaced the original 33+ year old radiator with a DeWitts repro radiator. If your rad has never been recored, if it is brass/copper, or is an aluminum one, it may not have adequate cooling capability.
Gary
My 66 had identical problems that were only solved when I replaced the original 33+ year old radiator with a DeWitts repro radiator. If your rad has never been recored, if it is brass/copper, or is an aluminum one, it may not have adequate cooling capability.
Gary
Race Director
Joined: Feb 1999
Posts: 19,659
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From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
I agree with the above. I had just rebuilt my motor and got the radiator flushed and flow checked. One of the first trips I made was about 10 miles up the road just normal driving at about 55-60 mph. The temp just kept climbing. I had a 180 degree thermostat and it just kept climbing. I turned and went home. I made the call around to check on radiators. The only local radiator that I could get that would go back in was going to be copper core not aluminum like stock. I made the call to Tom DeWitt and bought his reproduction radiator and have never seen above 200 again. The car will stick on 180 and I can drive 80 MPH and no worries. Idling in traffic it will get up to 200 and the SPAL fan will cool it off back to 180. I am convinced I had a water flow problem.
Guest
Posts: n/a
I know this may be a long shot. I had a 77 Vette that would only overheat or run hot on the highway at higher speeds. The radiator was good, timing straight, and it had a fresh thermostat. Turns out the upper radiator hose was installed without a ridgid spring (inside the hose) and at high RPMS, the suction of the water pump would actually suck the hose until it would collaspe, thus restricting water flow. I replaced the hose and all was well. Just my two cents worth.
Rick
Rick
Racer
Joined: Apr 2004
Posts: 271
Likes: 0
From: Alpharette GA
Rick we have problem on boats when the hoses get week and soft they collapse at higher rps and cause overheats. I personally would change both hoses and have the radiator boiled out after 30 some odd years it TIME.
