Legacy Outback 97 Intermittent Overheating

[villenes]

Need some input.

Our Subaru Outback 97 recently started blowing cold air when the heater was on. And shortly thereafter the temperature gauge started increasing, potentially overheating the engine. Immediately, turned the engine off and stopped.

At first we thought it was missing antifreeze. When we opened the radiator cap, the antifreeze burst out. We waited until it cooled and we filled the radiator. We did a short drive to test and noticed that we were getting extreme heat -- above normal temperatures however, the temperature gauge was reading normal.

According to the Subaru Owner's Manual, we bled the system at 2500 rpm for 5 minutes, waited one hour and repeated. It seemed to be fine that evening for our 500-km drive from Montreal to Toronto.

Whilst we were in Toronto, we took a small drive and started running into the same problem. The cold air started blowing with the heating at full and the temperature gauge started climbing. We brought it to a Subaru dealer while in Toronto and they claimed it was the head gasket (I doubt it was a true inspection since they provided the answer in less than half an hour).

Without having the job done, we took the car back and drove it to Montreal running into the problem intermittently early on in the trip. Somehow we made it back to the Montreal area and noticed that the temperature gauge climbed once again when we went from 100 to 120km.

(Note: During our return from Toronto, we had the heat running at high in order to avoid possible overheating.)

Looking forward to any input that can be provided.

 

[Carl 1 Lucky Texan]

Well, at least you did a better job than most folks at trying to purge
air from the coolant system. And, head gaskets are a known issue with
Phase1 2.5l engines. If the dealership sniffed the coolant for
combustion gases and got a pos. then they are right. I would like to
point out that a bad radiator cap or allowing the overflow to become
empty can cause the same problem on a soob. Due to the circulation
direction out of the radiator, any air can easily be entrained, if the
heater is on, the air will often collect in the core due to it being up
fairly high and prevent coolant flow. Undoubtedly air pockets collect
elsewhere in the engine causing local hot spots, steam explosions,
continued coolant loss - basically a runaway condition.

IIRC the key test for your situation is combustion products in the
coolant - search this issue on the forums at www.usmb.net for detailed info.

Carl
1 Lucky Texan

 

[xymergy]

Well, at least you did a better job than most folks at trying to purge
air from the coolant system. And, head gaskets are a known issue with
Phase1 2.5l engines.

Okay, we've got a 1999 Legacy Outback with the Phase 1 2.5 liter
engine, just had to have the entire fuel pump assembly replaced
because we discovered the low gas warning light didn't work (ran out
of gas, natch). The fuel sending units were faulty. So now I'm
worried about this head gasket issue because we do smell something,
not quite burning rubber, but something, sometimes after driving the
car. We have already complained to the dealer about occasionally
smelling fumes inside the car even with the recirculation button
pressed, and they found nothing. Should we follow up on the head
gasket: what symptoms are we looking for?

 

[Carl 1 Lucky Texan]

Does it smell sweet? Like carmel or marsmallows? That's the antifreeze.
Are you loosing coolant? Do you see or hear bubbles in the overflow
tank? Is there a film floating on top of the coolant in the radiator or
o'flow tank? Is there some chocolate mousse looking stuff on the
dipstick or the underside of the oil filler cap? You could have the
radiator tested for combustion products.

Never underestimate the ability of a Subaru to smell weird. In addition
to all the fluids and greases that can drip or be slung onto (like a
split CV boot) the exhaust, some folks are not diligent about changing
the in cabin airfilters and will start gowing mold on them.

do a search on headgaskets , coolant , over heating etc. on the forums
at www.usmb.net

Carl
1 Lucky Texan

 

[xymergy]

Does it smell sweet?

No, it smells like burning rubber, and I've noticed it mostly on the
front passenger side.

Are you loosing coolant? Do you see or hear bubbles in the overflow
tank? Is there a film floating on top of the coolant in the radiator or
o'flow tank? Is there some chocolate mousse looking stuff on the
dipstick or the underside of the oil filler cap? You could have the
radiator tested for combustion products.

I'll check all this stuff

Never underestimate the ability of a Subaru to smell weird. In addition
to all the fluids and greases that can drip or be slung onto (like a
split CV boot) the exhaust, some folks are not diligent about changing
the in cabin airfilters and will start gowing mold on them.

do a search on headgaskets , coolant , over heating etc. on the forums
at www.usmb.net

Thanks for this site, will look it over.

[original post below for reference, no need to read further if you are
already familiar with this thread]