My 1998 Outback has been overheating, I understand that the headgasket may be the problem, but so far all the tests have come back negative. We had the anti-freeze checked, the cylinder pressure checked and are now waiting for the oil sample to come back. The thermostat has been changed and the rad cap checked. What else can we check or what other information would help to find out what the problem would be.

There may be an air pocket problem. I have heard filling the system through the top radiator hose helps get rid of the air.

My 1998 Outback has been overheating, I understand that the headgasket may be the problem, but so far all the tests have come back negative. We had the anti-freeze checked, the cylinder pressure checked and are now waiting for the oil sample to come back. The thermostat has been changed and the rad cap checked. What else can we check or what other information would help to find out what the problem would be.

Water pump?

 

Also, I have heard that non-OEM thermostats have been problematic -- search the boards for more info.

see if your radiator is clogged

Well Brumby Boy, you may win the prizeless contest. My mechanic has tested the temperatures of the different hoses and parts of the engine. His theory yesterday was that the rad may be clogged. I guess it's coming out today. I'm glad that I didn't listen to the subaru dealer the first time it overheated, he was going to do the HG. That would have been $2000 CDN and then I would have been dealing with the rad. What a nightmare this has been.

The HG problem can look like a radiator problem because air gets into the system making it look like there isn't flow through the radiator. I'm willing to bet that a frequent series of replacements is thermostat, cap, radiator, water pump and then head gaskets. I just bought a 97 Legacy that had all the cooling parts replaced (nice new radiator!) and leaking head gaskets. I'm sure the previous owners just gave up after replacing all those parts and still having it overheat. If you have bubbles coming up through the coolant in the reservoir, or the coolant level in the reservoir rises and doesn't fall when it cools, or your temp guage is erratic, I would be concerned about the head gaskets.

Keep us posted.

See the thread "Another air in the coolant post..." Setright explains the cause and effect perfectly. One thing I don't understand is why a sniffer won't pick up the gases sometimes. There is plenty of them there!

Well, $2000 later(headgaskets and radiator), we're not overheating. We're taking our Outback on a good trip in a couple of days, so hopefully we're not sitting in some mountain pass waiting for BCAA again. This has got to be the most frustrating problem I have ever had with a vehicle. Subaru should be embarrassed.

Sorry you had that happen. If the job was done right you should have a lot of trouble free miles ahead with the car.