Weird thing that happened today. My 2001 Forester started off with no heat for about 20 mins. Then the heat started working. The temps were just around freezing (-1C, 32F). Hum, any ideas what could be happening? I thought about a stuck thermostat but the temp gauge showed normal and, the car didn’t overheat like what can happen if there is a stuck thermostat. Doesn’t make sense that it was an electrical problem because usually they don’t “get better”.
Cold then hot heater
- Thread starter GuyS1
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Check your coolant level
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Air bubble? Or stuck vent? Usually there is flow to the interior heater before the thermostat even opens, so it is odd that the engine had to warm up first.
Just one caveat, the temp sensor needs to be in contact with the coolant before it can read the correct temperature, so it can sometimes happen that the temp sensor reads cold when the engine is actually hot. This would happen if there was an air buble caused by low coolant level. If it was close to freezing, I would wonder if you have the proper amount of anti-freeze?
Just one caveat, the temp sensor needs to be in contact with the coolant before it can read the correct temperature, so it can sometimes happen that the temp sensor reads cold when the engine is actually hot. This would happen if there was an air buble caused by low coolant level. If it was close to freezing, I would wonder if you have the proper amount of anti-freeze?
I may have inadvertently posted this same issue elsewhere on the Forum….! I went to garage today hoping that a flush of the system would solve the problem (if the heater core or cooling system was the culprit, i.e….. plugged) but the technician said the coolant was all good and was within the maintenance replacement timelines. Not a likely suspect for my no heat problem.
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Intermittent problems are the hardest to figure out.
Science requires repeatability. Also, it requires independent verification, measurement, and so on.
Is it possible that the delay of the heating effect was purely subjective? (because it was so cold to start with?)
I would say, that one must keep a close watch on it and see if it happens again. (Or maybe it is normal?)
Science requires repeatability. Also, it requires independent verification, measurement, and so on.
Is it possible that the delay of the heating effect was purely subjective? (because it was so cold to start with?)
I would say, that one must keep a close watch on it and see if it happens again. (Or maybe it is normal?)
I’ve taken the cap off to see if there appears to be water circulating by the pump. No air bubbles, no leakage of antifreeze.
You are 100% right. I was going to throw a new thermostat in it, putting my faith in a resolution that just didn’t follow proper “diagnose” methods. It turns out the problem was a simple cable linkage slippage problem. The fix cost me nothing other than a good lesson. Fortunately for me, I didn’t buy the unnecessary thermostat replacement and the associated labor costs. That said, the Forum was an inclusive, invaluable brain storming resource.