'97 Outback with '96 2.2 engine. Once the car heats up, it sounds like a tap is running inside the car. This has to be noise from the heater core, but there are no leaks. Did a search, sounds like this is caused by air in the lines, so either head gaskets or rad cap. But I just did head gaskets (heads were machined, used subaru gaskets), water pump, thermostat, and rad cap. Tried parking on steep incline, removed radiater vent...topped off system to purge any air left...its been over a week now and this noise is driving me nuts. Maybe the headgaskets are still leaking? If this thing was a horse I'd shoot it...

I'd say you still have air in the system, and/or it's low on coolant.

 

Don't know if the 97 MY has the little vent screw on the passenger side of the radiator. But if it does, that needs to be removed to fully bleed the air from the system.

 

Look at the very top of the radiator on the passenger side and see if there is a screw/fitting that can be removed.

you know i've heard this before too, but i've never seen any associated issues with it like overheating or anything so it might be benign.

It does have that vent cap, which was removed twice now to bleed the air out. Maybe I'll just have to deal with it, but the last couple Outbacks I've had did not do this. I'll bet that head gasket still has a super slight leak...

I've had this on nearly every car I've ever owned. Never has hurt anything. I just deal with it.

Air bubbles gurgling through the radiator. It's a sign of improper filling of the coolant. You need to have the nose slightly in the air or bubbles will be trapped in the heater core.

 

GD

The nose was starting to get better...but still there...then the temp gauge pegged and coolant was being pushed out the overflow. No leaks anywhere, so am pretty sure I missed a crack on that driver's side head (the only one that was leaking...or really needed to be machined) If anyone has '95, '96 heads...please let me know...posted WTB ad as well...