71stockray

Have a strange highway problem. My 71 350/270 heats up to 240 on the gauge. Gauge is correct as per infared gun. New stat, new anti-freeze, new radiator, car runs fine 210 around town and mountain roads. After about 20 minutes at 75 tempeture starts to climb. On install of radiator, I put in all new foam seals. Also installed new factory spoiler, which helped a little, but not enought. I was wondering, the kit of the foam did not come with a peice to go between the top of the radiator and the radiator frame, leaving a 1" or so gap. Could this be causing the high temps at speed? Is there supposed to be a seal here? Any ideas would be great. Thanks :confused: :chevy SAVE THE WAVE

81' Corvette Guy

71..this small piece of foam could actually help lower your highway temps. Just think of how much air is being diverted over the top of the radiator. Pressure (air pressure) in this situation will always seek the path of least resistance. 75 miles an hour might not seem fast in car, but stand on the side of the road and let a car pass you at 75 miles an hour. So this 1'' opening above the radiator is ezier for the air to go over the top than to be pushed/pulled, depending on your fan set up..but, mainly pushed at 75 miles/ hour, through the radiator. If it were mine and would order the top foam and install and see what this does for you highway temps. Check the Doc Rebuild site for this piece, I am sure he has it..

Thanks, Joe..peace <*)))><


[Modified by 81' Corvette Guy, 8:39 AM 9/25/2003]

71stockray

I`ll add the foam. Thanks for the quick answer81'.

MIKER

Before spending money to buy a reproduction foam piece to fill the gap at the top of your radiator, fill the gap with a piece of foam pipe insulation. If this improves the overheating problem, you know that the correct reproduction foam piece will be worth the money spent.
I'm using foam pipe insulation to fill the gaps between my radiator and core support. It works great and I have no plans to change it. But, absolute originality is not required for my car.

Vetterodder

May not be the problem but check the function of both centrifugal and vacuum advance. As rpm and load are increased, too little advance can cause can cause higher temps. It's not that unusal for an old distributor to have it's advance plate sticking or for it's vacuum advance canister fail.