2002 2.5 - mysterious coolant issues

Had the oil changed the other day in my wife's Outback and as we were running errands I noticed the temp gauge running hot, pulled over to check and it immediately went back to normal. Made it home without overheating and checked the coolant resovoir, which was low, so I filled her up. Drove about 120 miles the next day no issues. Checked yesterday and the level was at Min, topped it off to the Max. Ran it last night and when I cranked it up I smelled coolant smell. Checked the fluid again this morning, it's at the Min. Started the car and did not smell the smell. She just called and said when she started it she did.

It has NOT overheated since last week. There are no obvious signs of leakage (no puddles or drips that I can see). Everything feels/runs normal, heat works, etc. I'm keeping a close eye on it, but now I'm beginning to wonder if it's something serious.

Any ideas? I'm hoping something minor, like a leaky hose to the heater box or something.

Thanks,
Ed

Have someone check the headgaskets.

You have the infamous 2.5. There is an additive that you use in the coolant. I think it's every 36,000 miles. You can only get it at a subaru dealer. I would recommend only using the additive that subaru sells. I've used Bar's leak for aluminum engines and it doesn't work as well.

had the same problem .It was the head gasket ...sorry..

ditto, i have a 1997 with a 2.5l engine and the headgaskets on it failed at about 120K miles...it's just a given the headgaskets will eventually fail on all subie 2.5s!

My 02 Ltd just had the head gasket fail at 190k. Same symptom as you. If you don't want the wife demanding a new car, get it fixed now before it strands her. There is an updated gasket which is supposed to not be prone to fail. I had my trusted mechanic do the gasket, rear main seal, new oil pan, small body work, and new headlight for $1400.

The car runs great again but I think there's either front hubs, tie rods, or mmotor mounts going because I've got vibration during acceleration.

Might have the mechanic check and see if the motor mounts are tight to the cross member and see if they're relatively centered. I've had a few that were loose and 1 that was off center.

You have the infamous 2.5. There is an additive that you use in the coolant. I think it's every 36,000 miles. You can only get it at a subaru dealer. I would recommend only using the additive that subaru sells. I've used Bar's leak for aluminum engines and it doesn't work as well.

The coolant additive is nothing more than stop leak relabeled. It is used to prevent water leaks to the OUTSIDE and NOT for head gasket failures between the combustion chamber and water passages. Obviously stop leak will not hold up to combustion chamber pressures.
Since it has overheated this is a typical symptom of the 2.5 HG failure.

Another symptom is exhaust in the coolant, this can be "smelled" by sniffing the recovery tank, it should not smell like exhaust, but if it does it is definitely a head gasket failure.