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2001 Subaru Outback over heating

I was driving my 2001 subaru outback a couple of months ago when it started overheating. I cooled it and drove it home. On my way home I noticed that if I pressed on the gas pedal it would soon be at normal operating temps(this trick also works when the car is in neutral and not moving). When I got home I discovered my coolant level was about 12 gal low. I filled it up and went on my way with no issues until two months later. It started over heating again and was again a 12 gal low on coolant. We discovered this at the start of a long road trip and filled it up again but by 800 mi. later it was again overheating and low on coolant. I have found yellow stuff in my overflow but don’t know how it got there. Both fans run fine and visible signs of a leak anywhere. AC still works, and the oil level is normal. Can anyone PLEASE help me?

Typo up there… there are NO signs of a leak anywhere.

All of these symptoms (loss of coolant with no external leak, “yellow stuff” in the overflow, overheating) add up–unfortunately–to a bad head gasket or two. This is a known problem with 4-cylinder 2.5 liter Subarus of the '97-'02 vintage (if I am recalling the specific model years correctly).

This needs to be attended to a.s.a.p., for two reasons:

Subarus do not take kindly to overheating, as a result of their aluminum engines, and warped heads are a possible bit of fallout of the overheating.

The “yellow stuff” that you see in the overflow is motor oil! Since motor oil is seeping into the coolant, and coolant is seeping into the cylinders where it is being burned, it is also likely that coolant is seeping into the motor oil. Coolant is not a lubricant, and after a short period of time, the engine will experience severe bearing wear as a result of the motor oil being diluted with coolant.

Although you did not provide us with the odometer mileage, it is possible that Subaru corporate may go “halfsies” with you on the replacement of the head gaskets, as long as you can substantiate that the car was maintained properly. If you did not have maintenance done at the dealership, this means that you have to produce all of your maintenance receipts from other service venues.

However, if your odometer mileage is too high (I don’t recall the cut-off for coverage on this repair), then Subaru will not go “halfsies” with you, even if it was properly maintained.

Please post back and let us know how you made out at the dealership.

Hi Brewer! Losing coolant slowly over 800 miles. I had similar problem on one 1997 Outback, 141K miles, which showed no leaking while idling nor when parked.
Replace the radiator cap first, Most times an aftermarket one [rated at @13 PSI, costs $8 bucks] does the job, sometimes the Subaru recommended OEM one doesn’t!

Next if that doesn’t fix loss problem: Check for Hydrocarbons[CO]in Coolant, either in reservoir or radiator itself; NAPA has a DIY kit for $50 bucks.
Then do a Cylinder pressure drop test to help confirm a begining possible head gasket leak starting.
Check this link to get great, clear desriptions:
Common symptoms:
“Sweet” smell after operating engine and then stopping.
External fluid leakage (yellow-green) Hood liner, or especially around overflow reservoir, or visible on/around engine.
Slowly dropping coolant level due to unseen leakage.
Also check/pull/test the t’stat, check fans/their fuses, and replace the radiator cap as above, check oil on dipstick to make sure that oil and coolant are not mixing and rest of reply as VDC so aptly describes. Good luck!