Subaru overheating

[blur911]

Went to pick up coffee yesterday in our Outback and noticed the temperature gauge going up too quickly...and continuing to go up.  Pulled over and let it cool, turned around and limped it back home.  No heat from HVAC, temp near the red.

I put about 3 liters of coolant and water in and while doing so noticed the hose going to the overflow was off.  I started it and after all the spillage was cooked off, couldn't find any leaks.  I think it might have just slowly emptied itself through the disconnected overflow.

Anyhow, I'm going to get some Subaru coolant conditioner, which is apparently repackaged Holt's Radweld and see how that works.  I can still slightly smell coolant, not sure if small leak or just from yesterday's spillage.

[Bubba]

Hopefully, the disconnected overflow was the root of the problem.

[blur911]

I'm used to FGCs that have a sensor for everything and tell you coolant is low.  Subaru doesn't.
Anyhow, all seems well, put in the coolant conditioner/stopleak and drove around for half hour in the burbs, no leaks and temp stayed steady...so I sent the wife off to Trenton in it.

[Johnnymac]

Well sounds like you avoided anything major.  Hopefully it's just a bit of residue that is giving you that smell of coolant.

[blur911]

So far so good with the overheating.
 
Of course she called me to tell me that Err55 (wheel speed sensor) popped up on the dash and the ABS and cruise control stopped working on the way there, was ok on the way back.
I think it needs front wheel bearings, ordered a pair, going to change them when I do the axles.

[RRocket]

Always something...

[blur911]

Noticed the temperature creeping up again yesterday.  Checked and the overflow tank it was about to overflow and the radiator was low.
Think it might just need a new radiator cap, think coolant is going out, but not going back into the radiator.

[Firm]

What year and engine? Cap is a possibility, also make sure that the hose from the overflow back to the radiator to the isn't kinked, or collapsing.
I hope it's not the case, but Subaru has a thing for headgaskets, which could be putting combustion pressure into the system and displacing the coolant. If you go out to grab a cap might be a good idea to grab one of those test kits that checks for combustion gases in the system, just to rule it out.

[blur911]

What year and engine? Cap is a possibility, also make sure that the hose from the overflow back to the radiator to the isn't kinked, or collapsing.
I hope it's not the case, but Subaru has a thing for headgaskets, which could be putting combustion pressure into the system and displacing the coolant. If you go out to grab a cap might be a good idea to grab one of those test kits that checks for combustion gases in the system, just to rule it out.

It's an '05 with a 2.5, no turbo.
Pretty sure it's not a head gasket, BTDT with our previous Outback VDC.  No bubbles in coolant, went for weeks between top-ups.
I just replaced the rad cap with a new one.  I messaged the previous owner who is a friend of mine, he had similar issues years ago with it and he said it turned out to be a rad cap.