Anyone else have overcooling?
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Anyone else have overcooling?
My mostly trusty '90 wagon has an intermittant no heat problem. The engine won't heat up normally and when it does heat up at all, turning on the heater blower brings the gauge down to C. Just going down hills can cause it to start cooling off. I have replaced the thermostat 3 times, it has a new radiator, waterpump, cap and the cooling system has been flushed. All these things have made no change.
There is no air in the system and it doesn't mix oil and coolant. The upper radiator hose is hot but the lower one is just barely warm when the problem occurs. The heater control knob is active. Right now I have a piece of cardboard over the complete radiator ( 3"x 3") hole in the center and it doesn't even come close to overheating. The gauge is accurate but doesn't quite go to the "normal" point, it's always towards cold by 1/16". Under no conditions will the cooling fans come on, even when indoors, reving at 3k for 10 minutes. An infrared detector show the upper hose temp at 170 and the lower at 90.
My mechanic w/30 years of experience says that he's only seen overcooling once before and he didn't solve it
There is a post on this forum with the same problem but no real solution: [URL=http:// https://www.honda-acura.net/forums/showthread.php?p=1587375#post1587375]
Winter here in the northeast doesn't plan on leaving soon...any help would be more that appreciated. Thanks.
There is no air in the system and it doesn't mix oil and coolant. The upper radiator hose is hot but the lower one is just barely warm when the problem occurs. The heater control knob is active. Right now I have a piece of cardboard over the complete radiator ( 3"x 3") hole in the center and it doesn't even come close to overheating. The gauge is accurate but doesn't quite go to the "normal" point, it's always towards cold by 1/16". Under no conditions will the cooling fans come on, even when indoors, reving at 3k for 10 minutes. An infrared detector show the upper hose temp at 170 and the lower at 90.
My mechanic w/30 years of experience says that he's only seen overcooling once before and he didn't solve it
There is a post on this forum with the same problem but no real solution: [URL=http:// https://www.honda-acura.net/forums/showthread.php?p=1587375#post1587375]
Winter here in the northeast doesn't plan on leaving soon...any help would be more that appreciated. Thanks.
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From: Cupertino, CA
Well, let's think. It wouldn't be a water pump or thermostat problem, as once the thermostat is open, it stays open, so any nonsense about it being stuck open and causing overcooling is just that. The water pump spins with the T-belt, so that's engine-controlled and it can't be the problem, unless it's the wrong water pump for your engine and somebody managed to get it to fit. Then perhaps it circulates coolant too quickly (remember there is a gearing issue with belt-driven water pumps), however this seems really, really unlikely.
As for the coolant temp sensor, it depends which one you mean. There are 2 temp sensors, one for the ECU and one for the gauge. For the symptoms he described to be all happening at the same time (low temp reading on gauge AND no radiator fan turn-on), both gauges would have to be malfunctioning, which is unlikely, however given that overcooling is an unlikely situation in the first place, it seems possible (and definately more possible than the water pump idea).
civicwagonsonly, are you experiencing any problem you would otherwise associate with overheating, like perhaps burning coolant out the tailpipe from a busted head gasket? Maybe there's blockage at your upper radiator hose. But I would guess that when you flushed the system this would have been discovered.
Man, that's a doozy.
As for the coolant temp sensor, it depends which one you mean. There are 2 temp sensors, one for the ECU and one for the gauge. For the symptoms he described to be all happening at the same time (low temp reading on gauge AND no radiator fan turn-on), both gauges would have to be malfunctioning, which is unlikely, however given that overcooling is an unlikely situation in the first place, it seems possible (and definately more possible than the water pump idea).
civicwagonsonly, are you experiencing any problem you would otherwise associate with overheating, like perhaps burning coolant out the tailpipe from a busted head gasket? Maybe there's blockage at your upper radiator hose. But I would guess that when you flushed the system this would have been discovered.
Man, that's a doozy.
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is your computer throwin any codes at you?
The only time the "check engine" light comes on is rarely when I climb a hill with within the first 2 miles after starting up. The led still only shows one flash. Restarting the engine shuts off the "check engine" light.
The only time the "check engine" light comes on is rarely when I climb a hill with within the first 2 miles after starting up. The led still only shows one flash. Restarting the engine shuts off the "check engine" light.
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Joined: Dec 2004
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From: San Jose, CA
Is it a Honda thermostat or an aftermarket one?
(someone in a prior topic said the OEM thermostat is very well made; as opposed to an inexpensive aftermarket thermostat that saves you $10 to $20 and gives you headaches)
Also, what temperature thermostat is currently in your car? a low temp one will cause overcooling.
If the coolant returning from the radiator is cooling the engine too much, the thermostat should closeup (keeping the engine at proper operating temp). (maybe, the one you have isn't doing that.)
(someone in a prior topic said the OEM thermostat is very well made; as opposed to an inexpensive aftermarket thermostat that saves you $10 to $20 and gives you headaches)
Also, what temperature thermostat is currently in your car? a low temp one will cause overcooling.
If the coolant returning from the radiator is cooling the engine too much, the thermostat should closeup (keeping the engine at proper operating temp). (maybe, the one you have isn't doing that.)
2 tone Rex
Joined: Jan 2005
Posts: 755
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From: Alexandria, LA
Originally Posted by augy
Well, let's think. It wouldn't be a water pump or thermostat problem, as once the thermostat is open, it stays open, so any nonsense about it being stuck open and causing overcooling is just that.
