dmay4

Ha go figure yea first set of HG was replaced at about 140,000 miles. Both fans come on when AC is turned on. We have replaced the radiator So I don’t think its plugged. I have just put on probably 125 miles with no problems knock on wood… After about 45 minute drive to work/home I did notice very little bubbling in reservoir, but not flowing over .

Exhaust test in antifreeze?? If thats positive is it a dead ringer?? Bad HG????

Well I cant be sure what type of HG was used, I am assuming non-OEM (place is out of business) Prior to HG replacement never really overheated if it did stopped right away. HG repair was done over 2 years ago and had no problems till now. We added air pressure via each cylinder and produced no bubbles in coolant system wouldn't this confirm a HG leak??

I have a 2001 Subaru Outback Sedan 4Cyl. 190,000 miles and love the car. About 40,000 miles ago we had head gaskets replaced because they were blown. Recently car has been overheating. So I changed thermostat (have gone through quite a few, now running OEM T-stat) problem continued. Normally runs just below half on temp gauge, would fluctuates then peg to top. We stop wait to cool add water and get it home. So far we have replaced radiator, and cap, ran a coolant conditioner through with intention of sealing any head leaks, replaced water pump, ran compression test on coolant system and holds pressure overnight. Back pressured tested each cylinder with no air through coolant system. No water visible in oil. Symptoms persist; I can drive at highway speeds in summer temps for up to 60-70 miles or so then it over heats, coolant back flows into reservoir. I am at a loss any ideas???