Overheating 454
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Overheating 454
Can someone help, I have a 454 new rebuilt motor in a 1978 corvette, new 3 core aluminum radiator with 2 12 " fans, new water pump , 160degree thermostat , motor runs at 200 degrees when hot ,does not fill the overflow tank, how can I test to see if something is blocked.
also upper radiator hose seems to swell,
Thanks
also upper radiator hose seems to swell,
Thanks
Race Director
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From: Wellington, FL
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Is the rad full when cold? If not, water expansion may not reach the overflow tank. Re the 160 stat, be aware that running this low temp stat will create condensation problems in the oil and exhaust system if the engine is not brought up to operating temp which takes longer than with a 180 or 195.
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Drifting
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From: Cartersville GA
Double check that the gauge is reading correctly....My 72 read between 210-230 on my initial drive home, so I installed another temp gauge that I tested and while the original gauge read around 215 actual temp was around 190 on the new gauge.
Brian
Brian
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Havent really had it on the road to long but it seems very hot the temp gauge climbs towards 220, I have discs on the back of the heads that popped ,the engine builder put them there to warn of overheat and they popped
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Thread Starter
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Rookie question: Is it possible from what I've read that the 160* thermostat allows the coolant to circulate too fast (similar to central A/C unit in a home where a "high rpm" forced air fan pushes air past the cooling coils too fast for the air to reach it's coolest temperature)----the engine coolant does not have time to release enough heat?
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Is the rad full when cold? If not, water expansion may not reach the overflow tank. Re the 160 stat, be aware that running this low temp stat will create condensation problems in the oil and exhaust system if the engine is not brought up to operating temp which takes longer than with a 180 or 195.
Race Director
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From: Wellington, FL
St. Jude Donor '11 thru '25
I'm afraid that's BS. Whatever stat is used, the engine will eventually reach its normal operating temp (as long as it's not rated at a higher temp). Some are of the incorrect opinion that the temp of the stat is where the engine will operate. The stat temp only tells you at what temp it will open allowing passage of coolant.
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From: Austin Texas
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my 500hp 454 runs at 165 degrees, 160 T-stat with a stock cleaned Radiator.
if your temperature is more than 20 degrees above your thermostat,
you may an issue. I think you still have air in your system.
it can be difficult to remove air in a corvette.
if your temperature is more than 20 degrees above your thermostat,
you may an issue. I think you still have air in your system.
it can be difficult to remove air in a corvette.
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any ideas on how to do that
Racer
Joined: Jun 2012
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From: New Britain Connecticut
I don't have a 454 but A 427.the overflow tank is where you check the coolant leval.
Their is no cap on the radiator.the overflow tank should have coolant in it.car runs at about 210 city.add collant to the overflow tank if needed,with the cap off the overflow tank warm up the car.rev the gas high.it should gulp in the needed coolant.any extra coolant should come out the overfill tube.
Their is no cap on the radiator.the overflow tank should have coolant in it.car runs at about 210 city.add collant to the overflow tank if needed,with the cap off the overflow tank warm up the car.rev the gas high.it should gulp in the needed coolant.any extra coolant should come out the overfill tube.
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Air-Lock there are several ways to address, the problem is the engine sits higher than the radiator if you trap air in the engine, it profits heat transfer to the water, I personally fill my system via holding the top radiator hose-up and pouring in until it comes out your overflow or radiator.
upon installing a new 454 motor I had the same initial problems it would continue to heat up to 220 or so, to hot for me, I add to refill my system like 3-4 times,
once I got it right, the temperatures would raise to 165, and sit there solid and no longer continue to increase temperature.
upon installing a new 454 motor I had the same initial problems it would continue to heat up to 220 or so, to hot for me, I add to refill my system like 3-4 times,
once I got it right, the temperatures would raise to 165, and sit there solid and no longer continue to increase temperature.
Last edited by 69Vett; Aug 10, 2015 at 03:43 PM.
Melting Slicks
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To maximize cooling at moderate speeds .....GM put a lot of cut shapedfoam pieces around the shrould to help force the air though the radiator . ......moving your car should drop temp from T stat range , not increase . My car idles on a 90 degree day sitting still 195 -200. .....but once I'm moving it will drop back to 180 190 range and that's on a HOT azz day . 200 is ok long as it backs down once your under way.....as air flow is induced.
THere was a special spoiler extension used on LS4 73 -74 with AC .....5 inch or so stiff rubber dam was riveted to the small plastic lip to help force air up though the lower cooling slots .
It does make a nice difference at speed. Very difficult to find factory piece. But you might make one up.
Also my car came with a big 7 blade fan and fan clutch . These work well too ......I replaced my fan clutch 20 years ago .....still all good.
THere was a special spoiler extension used on LS4 73 -74 with AC .....5 inch or so stiff rubber dam was riveted to the small plastic lip to help force air up though the lower cooling slots .
It does make a nice difference at speed. Very difficult to find factory piece. But you might make one up.
Also my car came with a big 7 blade fan and fan clutch . These work well too ......I replaced my fan clutch 20 years ago .....still all good.
Last edited by LS4 PILOT; Aug 10, 2015 at 07:21 PM.