Does anyone know of a good independent Subaru mechanic in the Great Falls MT area? I've got a '99 Legacy GT, 2.5 with 160,000 miles that suddenly started overheating. I think it's the thermostat because the top rad hose is hot but the bottom is cold so the water is obviously not going through the radiator. And as it's cooling down the top hose starts collapsing which makes me think the thermostat is sticking shut. I'm an old Chevy guy so if it's more than just a thermostat I'm not thrilled about doing it myself.

Isthe radiator level low, and the resevoir tank level high?

Are you getting lots of airbubbles in the overflow when the car is running?

Is the radiator level low, and the resevoir tank level high?

Are you getting lots of airbubbles in the overflow when the car is running?

Rad was low (1/3 gal) and the overflow tank filled up. No bubbles that I could see. The strange thing was watching the top hose suck flat as the motor cooled down. Are you thinking head gasket? Would it blow all of a sudden with no external leaks, no prior water consumption or water in the oil?

Just looked at it this morning and the bottom hose was also sucked flat. I removed the rad cap and there was a suction "whoosh". The thermostat has gotta be stuck shut, right?

Edited December 9, 201114 yr by C5INC

Sounds like a bad rad cap. Cheap and easy to try first.

I got the new thermostat in and it looks like that was the problem. Still need to get it out on the road to be sure but it ran normal for close to an hour in the shop.