Subaru Outback Overheating- intermittently
Recently purchased a 2008 Subaru Outback
with the 2.5. I no sooner got it home & it
started overheating. I drained the coolant,
replaced the thermostat, radiator cap with no
such luck. Its totally intermittent. For instance
I drove it around town for a good 30 minutes
& freeway speeds for another 20 or so and
no issues. I let it cool down completely &
tried it again. By the time I got it home it
started ping'n almost into the red. Totally at a
loss. Assuming it may be a head gasket
given the 2.5 reputation. I drained the oil
though & saw no indication coolant. And no
external leaks from what I can see. At about
2500 rpm I do hear a rattle. I thought it was
just something loose in the exhaust system &
it's resonating at that rpm. It doesn’t rattle
below or above that rpm though. Thoughts?