(w/178k miles) when idling does not overheat at all. If does overheat
when it is in drive. Does that mean that the headgaskets are gone or
could it be something else? Thanks.
Hi,
Forgive me, since I didn't pay a lot of attention to the thread when you
first asked about your overheating questions: are you still on the
original radiator? If so, it's possibly become partially clogged over
time--some say about 100k miles is a reasonable service life for Subie
radiators due to the smallish passages in the core.
It's very likely from your description here that you have enough cooling
capacity as long as the engine's not under load. That often matches
others' experiences with clogged radiators, including mine. Also, some
Subies come w/ single row cores in their radiators, some w/ double row.
If yours has a single row, you may benefit from a double row as a
replacement. I've used
www.radiator.com to get a good quality double row
at little more than the price of a single row.
Other oddball things to check are the thermostat (go OEM here--some
aftermarket units don't flow as much coolant), your fan(s) and your
hoses. A weak (soft) lower hose can partially collapse at higher speeds
and restrict flow, which, of course, is impossible to see in action.
Also, when replacing coolant, a 50-50 mix of coolant with DISTILLED
water will help prevent future clogging, as well as providing the best
overall combo of anti-freeze and anti-boil protection for most areas
(you can go up to 70% coolant w/ most brands, but the added benefits are
small unless you live in a really frigid area.)
Best of luck!
Rick
