I have a 1998 Subaru outback (automatic) with 117,000 miles on it. It had started to overheat , and we flushed the system to get rid of any sludge, and changed the thermostat. Still overheating. Brought it to the Subaru dealership and asked that they do a compression test to make sure it wasn’t the head gasket. They could not get it to overheat, and told us they thought it was just air in the system. One day after getting the car back it overheated again. Symptoms I noticed : The car would blow plenty of heat and then suddenly blow cold. As the cold air came in, the temp. gauge would rise quickly. At the same time, I noticed that while accelerating (to find a safe spot to pull over) the engine would rev way up and not shift down like normal. Sound like a head gasket? Why the inconsistency of the symptoms? Just want some idea of what to ask for when calling Subaru back.
Is the car losing coolant?? A blown head gasket will force the coolant out of the engine and into the recovery tank, which gets full and overflows. The radiator will be pressurized even though the engine is cool…The recovery system no longer works because a vacuum never forms in the radiator to draw the coolant back in…
After a flush, sometimes it is necessary to disconnect one of the heater hoses to purge all the air out of the system. When the heater blows cold and then the car overheats, that’s a sign of low coolant level…
The dealership stated that the coolant level WAS very low when it was brought in. It was at the right level when we picked it up yesterday and drove it home.Then when it overheated ,I could hear a gurgling,bubbley sound from the front of the car.White steam (smoke?)also seeped out from under the hood (from overflowing coolant?). Was hoping maybe just a leak in a hose was making us lose coolant, but I don’t see any noticeable leaks (puddles under the car,etc…), so I can’t figure out where this coolant is going.