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Old 07-01-2008, 06:02 PM   #116 (permalink)
Formula413
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Join Date: Jan 2008
Location: In the Northeast dreaming of the Southwest
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Aegean C - '17 Honda Civic LX
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Quote:
Originally Posted by garys_1k View Post
I guess I see the above as exactly the reason you can NOT shut off the heater core flow, but instead bypass the core if you don't want heat in the pass. compartment. Shutting that flow off means your engine has zero coolant flow until (and if, a big IF with no flow to it) the thermostat opens. I could imagine some pretty nasty local overheating in the heads, especially by the exhaust ports, with zero flow.
Actually, that got me thinking, so I had to go out and look. Sure enough, the lines through the heater core are the only thing allowing coolant circulation until the thermostat opens. I guess I was imagining some other hose that served this function, but if there was such a hose, there would be nothing to force coolant to go through the heater core and get it hot. I don't have my engineering degree yet. So the proper way to do this would be to put a diverter valve into the heater core feed line and run one outlet to the core and one to a tee in the heater return line. But then we are just back to the question of: Will this actually have any benefit, since this is just wasted heat anyways? The only possible benefit might be cooler vent air, as speculated below...
Quote:
Originally Posted by garys_1k View Post
After a hot soak the vent air coming out, with the temp. control set to full cold (no A/C) is much warmer than the outside air. Some of that heat could be from the ducts, heated from sun on the hood, but I suspect most of it originates from that hot core warming up the whole works.
I have noticed this too, sometimes I will run my A/C briefly to help cool this air down and then switch back to normal vent mode. I don't, however, know for sure where that heat is coming from.
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