The water pump gasket in my '98 Forester (130k) recently began to leak, and I will be replacing it in the next couple days. I noticed a stream of bubbles in my overflow container, though, and am wondering if it might be bad head gaskets making the air bubbles. The bubbles only appear after the engine is warmed up, like after a drive around town - there aren't any bubbles when the engine is cold.Is it possible that these air bubbles are coming from the leaking water pump? I hope so, because I'd much rather replace the pump than the head gaskets!
Yes it is from the leaky water pump. Because it is leaking it will most prob be sucking air. If it was a head gasket you would notice it when cold as well
I have yet to witness a leaky water pump suck air into the cooling system . If you are seeing bubbles in your radiator after the vehicle heats up see if the temperature is also higher [the hot gasses will heat up your coolant and eventually can push your antifreeze to the reservoir tank ] it can result in boil over.I strongly believe you have a bad head gasket that has not entirely blown yet Have the compression checked per cylinder,and for water getting into your oil (it would become a milky brown and become frothy a little bit) if that is all ok, then maybe just maybe a pump sucking air is occurring, though I have never seen it or herd of it before in my entire life.
You have a blown head gasket
