Lukewarm heater
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Intermediate
Joined: Nov 2009
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Lukewarm heater
I've got a 78 with an unique, for a Corvette, problem. I've installed a mild 454 with a stock aluminum intake. Only my heater is warm at best! The heater control valve is open, the hoses are new and not kinked, the thermostat has been replace (180 degrees). I replaced the heater core a few years ago; I thought that it might have become clogged somehow, but I just got done reverse flushing it with one of those drill pumps and the water flowed easily through the entire system and back out into my catch bucket.
I'm gonna try a 195 degree thermostat and have drilled a small hole in it to hopefully bleed off any air bubbles. Anybody got any suggestions? The heat seems to come up amlittle bit more thge faster the motor turns.....
I'm gonna try a 195 degree thermostat and have drilled a small hole in it to hopefully bleed off any air bubbles. Anybody got any suggestions? The heat seems to come up amlittle bit more thge faster the motor turns.....
Drifting
Joined: Jun 2025
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Perhaps the remainder of your cooling system (including water jackets in block/heads/intake manifold) is fouled with a combination of rust/scale/sediment/sludge ?
the correct strong chemicals + heat + time + engine's recirculation will clean it; there's a process.
the correct strong chemicals + heat + time + engine's recirculation will clean it; there's a process.
Thread Starter
Intermediate
Joined: Nov 2009
Posts: 32
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I had changed the intake from cast iron to aluminum and it was clean going on. The motor itself I personally built and shoehorned into the car. Doesn't mean that something couldn't have formed, but it appears unlikely. The heater was working until this year. There appears to be good water flow from the thermostat housing into the core and then back into the water pump.
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Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Is my vette stock?? HAHA
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From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Where do you live, what is the ambient air temperature when this issue occurs , what does your temperature gauge indicate for engine heat.
When its below 60*f up here in taxachusetts my 427 stays very cool as well and the heater doesnt throw heat because the engine stays cool well below 180*. Ive had to leave for shows a few times at dawn when it was well below 50* f
I throw a piece of cardboard in front of the radiator so the cooling air has to go around it, it slows the air flow and my engine can heat up to 190 or so. When the outside air temp comes up i take the cardboard out. Otherwise you need to swap thermostats for a 195* and then again to a cooler one when the air temp warms up....pita, just use the cardboard
When its below 60*f up here in taxachusetts my 427 stays very cool as well and the heater doesnt throw heat because the engine stays cool well below 180*. Ive had to leave for shows a few times at dawn when it was well below 50* f
I throw a piece of cardboard in front of the radiator so the cooling air has to go around it, it slows the air flow and my engine can heat up to 190 or so. When the outside air temp comes up i take the cardboard out. Otherwise you need to swap thermostats for a 195* and then again to a cooler one when the air temp warms up....pita, just use the cardboard
