I got my 02 Outback back from having an engine rebuild. (I know, shame on me for not watching the oil). It runs great now, but the coolant is not flowing back from the overflow after running for 30 minutes (my commute home)
I noted the tank level, topped off the coolant and drove home. When I get there, the overflow level is 8 oz higher than when I left. That makes sense as the coolant heats and expands. I leave the car overnight and the next morning check the levels. The overflow level hasn't changed and when I pull the radiator cap, there is a vacuum. At this point the radiator is 8 oz short of coolant.
If I don't open and refill the radiator, when I get to work, the overflow has 8 more oz in it and the radiator is 16 oz down.
What the heck is going on here?
We have replaced the cap, the radiator and the thermostat with original Subie parts.
Any ideas?