This happened to me. I have a 91 Subaru Legacy L 2.2 automatic. Coincidently I also have 162,000 miles. It started with getting the cold air when the heater was on. Then my car started overheating but would return to normal temperature after a half mile or so. My coolant was also leaking but not from the radiator. I would just add new coolant every week or so. After about a month of this my car started to howl every time I would start it and continue to howl until I would put it into drive. This was a pretty good clue that I had a bad water pump (or seal, either way the pump and seal need replaced). Also the car would leak water (who can afford to keep filling a radiator with anti-freeze if it just leaks out in an hour?) From the timing belt cover.
It really sounds like it is a bad water pump. I had all the same things happen to me. Watch out because the overheating can ruin your thermostat and your car can overhead without showing it on the instrument panel.
Here are some ways to check if your water pump is bad:
"Two most common signs of water pump failure are coolant leakage and/or a howling or screeching sound. Don't mistake drive-belt slippage, which causes a squealing sound, for water pump bearing failure. If a squealing sound is heard, check the drive belt tension and condition"
-Haynes Subaru Legacy repair Manuel 1990-1999 (Section 3-6)
You can Google more signs and symptoms of a bad water pump if needed.
I am currently in the process of trying to fix my water pump. It is slightly difficult because its driven off the timing belt and the crank pulley and cover must be removed to access the pump. I have yet to complete the project but it is giving me a great opportunity to replace the timing belt and radiator hoses.
Hope this helped a little, good luck,
Mike Bell -broke college student who must fix his beloved 91 Subaru to have transportation
Tuesday, April 20th, 2010 AT 11:17 AM