Hot 71 454 C3
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Heel & Toe
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Hot 71 454 C3
Bought a 71 4 speed 454 last summer and had to replace the old incorrect rad and cooling fan with a stock rad and correct 7 blade fan. I live in Southern California. It runs a lot cooler than it did but I have found that whenever I drive it for over 30 mins or more (freeway or street) in warm temps it seems to run cool enough, but then I park it and it dumps some coolant. I have read here that the best solution for this is to install a 3 row aluminum rad. Anyone agree? Just looking for some experienced advice.
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Safety Car
Joined: Sep 2007
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From: Indy Indiana
install a thermostat that is one step cooler than what you have in it now.
my 454 would spit coolant after shutting it down with a 195, it does not with a 180. it has a stock radiator and fan/clutch.
my 454 would spit coolant after shutting it down with a 195, it does not with a 180. it has a stock radiator and fan/clutch.
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Heel & Toe
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Cheers!
Le Mans Master
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From: Tampa Bay FL
Is the recovery tank located at the proper height in the engine compartment to ensure it is not too high or low compared to the rest of the cooling system? Also, is it a stock recovery tank and is the coolant at the correct 'cold' level before driving?
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Heel & Toe
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Burning Brakes
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It is a stock recovery tank in the stock location. The recovery tank is metal so I cannot see the cold verses hot coolant level as you can with a plastic tank. I can only see with the cap off when re-filling. Then Istop filling when coolant is visible in the recovery tank neck. I normally only refill one the engine is cold.
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The coolant recovery tank should be 1/2 full. It will puke fluid after shutdown if it is filled to the neck. A Dewitt's aluminum radiator is always an improvement over an older radiator or a copper brass radiator. My big block went down almost 30 degrees after I installed one. It would run 210-220 after prolonged highway drives in the summer. Ir runs about 180-190 now.
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Le Mans Master
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From: Butler Pa
The coolant recovery tank should be 1/2 full. It will puke fluid after shutdown if it is filled to the neck. A Dewitt's aluminum radiator is always an improvement over an older radiator or a copper brass radiator. My big block went down almost 30 degrees after I installed one. It would run 210-220 after prolonged highway drives in the summer. Ir runs about 180-190 now.
My big block runs 180 all the time. I'm using the original copper brass small block radiator that came in a '69. If you need to buy a Dewitts radiator to keep from overheating, you're just covering up another problem.
Safety Car
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From: Indy Indiana
I kind of guessed it is caused by hot spots inside the engine. as the coolant is no longer circulated after shut down, it starts to boil, further increasing the pressure and causing the dump. a common big block characteristic.
could also be retarded timing causing you to run a little hotter. check your timing and perhaps advance it a little.
then you are getting more into researching your advance curve, with too stiff springs and a too slow vacumm advance that you can look into.
lots of little cheap things you can try before dumping money into a new rad.
could also be retarded timing causing you to run a little hotter. check your timing and perhaps advance it a little.
then you are getting more into researching your advance curve, with too stiff springs and a too slow vacumm advance that you can look into.
lots of little cheap things you can try before dumping money into a new rad.
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No Corvette prior to 1973 came from the factory with a recovery tank. If you have an external tank of some sort and it's stock, it's an expansion tank. Very different animal.
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Now there's a unique solution, just throw money at it.
My big block runs 180 all the time. I'm using the original copper brass small block radiator that came in a '69. If you need to buy a Dewitts radiator to keep from overheating, you're just covering up another problem.
My big block runs 180 all the time. I'm using the original copper brass small block radiator that came in a '69. If you need to buy a Dewitts radiator to keep from overheating, you're just covering up another problem.
Actually my old copper/brass radiator was pretty well shot. I've changed from copper brass to aluminum on 2 other cars I've owned and saw dramatic reductions in temps with everything else functioning properly. If yours is running 180 you obviously don't need a radiator. I've never had a big block or small block with a copper brass radiator that would run 180 in the summer. That's my experience with them.
Le Mans Master
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From: Butler Pa
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Heel & Toe
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Looks like this: http://www.zip-corvette.com/_Images%...s%5CM-3890.JPG
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Heel & Toe
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I installed a new 180 thermostat this past weekend and it made a big difference. Seems to be running much cooler, and no more coolant dump after engine is stop. Thanks again for the tip!