Questions and Answers

Subaru Overheat/No Heat

Q. When I let my Subaru idle with the heat on, it soon starts blowing out cool air while the water temperature gauge climbs near to overheating. What do you think is the problem?

Thanks,
David

A. I think the most likely cause is a bad water pump. Over time the fins that move the coolant through the engine corrode away and you do not get a proper flow. It might also be a stuck thermostat. But that would cause an overheat, but still give you high heat from the heater.

You might want to throw a thermostat in just to confirm that it is not the problem, then look at the water pump.