misteradio

Ricearu, you are a genius. Took the car to mechanic this morning. He found a "Large air pocket" in the system, removed it. Car runs fine....for now. Thanks all for your assistance!

Thanks, Ricearu. I think I've done that correctly, but maybe not. I'll try again. Appreciate your help.

Thanks, GD. i have replaced radiator, thermostat and hoses. Bled air from the cooling system (run vehicle until coolant starts to overflow from the bleed valve). CHanged oil and didn't see any signs of water in it. I'm stumped. Hoping not head gaskets, but testing for that is my next step.

My son just bought his first car, a '90 Legacy L wagon w/EJ22, 180k. Purchased from Subaru mechanic, who claimed to have recently replaced head gaskets and water pump. Car now overheats, but only when driven. It can idle in 100-deg. heat with a/c on for half hour and temp gauge never rises above 1/2 way. Take it out on the street and it overheats within 5 minutes. Have replaced radiator and hoses and I believe we've bled air from coolant correctly. No apparent leaks while car is running, no noticeable smoke from tailpipe. Both fans work. Upper hose is warm to touch, but not overly hot. Radiator cap (also new) is warm as well. Bottom hose feels cooler, but not "cold" after car idles 10 min or so. There does appear to be some condensation in oil, which I know can be bad news. I've read that EJ22s don't typically leak coolant into engine oil..so I'm curious how any liquid would get in there. What would cause car to overheat when driven, but not with extended idle? Any expert recs on what this could be - if not HGs?