Overheating issues

I have a subaru legacy outback that is now overheating constantly and I think it continues to lose water. I don't drive my car on the freeway anymore. I try to keep it under 55mph and it seems to overheat less. I have no idea what it could be. I took it to a radiator mechanic and they replaced the plastic parts where the hoses are attached because those pieces were cracked. I also put a new radiator hose on because that blew. Excessive pressure still builds up in the hose and you can actually hear the water boiling. The mechanic didn't think it was the thermostat because when the radiator is filled, the car doesn't overheat. What would cause the car to lose water? The radiator doesn't leak and the inside of the radiator is clean. I get it flushed at least once every two years. I just drove to work this morning and the fluid was just pouring out of the overflow by the time I actually made it to the office.

Engine overheats almost immediately after starting. Radiator is full. Was told it might be a blown head gasket. How do I diagnose the problem?

Thank you

I have a 1995 subaru legacy with a overheating issue, radiator was flushed and burped and still overheats after 10 mins of driving it makes no sense. Mechanics are not sure whats going on or never worked on a subaru before, coolant has no bubbles so I doubt its headgasket, maybe thermostat. Water pump but im hoping its a easy fix. Please help.

Im having a issue getting the two bolts off of the thermostat housing someone has stripped them and they are rusty so all attempts to take it off have been unsuccessful im not sure how im going to get these bolts off. Is a leak down test usually free?

Sometimes the car overheats after driving 3-4 miles, other times after driving 12-15 miles it doesn't overheat at all. Once when it was hot, I took the bleeder plug out and steam was shooting 2 feet in the air, at the same time you could stick your finger in the coolant in the opposite side of the radiator. The dealer said the headgaskets were blown, the car ran w/o any misses/hesitation at low or high speed. Wouldn't bad headgaskets affect performance? Could the overheating be caused by something else? (Something less expensive to repair $1,900)
Thanks, Dan

I would suggest that the thermostat is sticking shut sometimes. Aftermarket thermostats are mostly made in China and have spotty quality control, best to get the OEM replacement from a dealer (no, I don't work for a dealer or know anyone who does).

Engine Cooling problem
1991 Subaru Legacy 4 cyl Front Wheel Drive Automatic

We have replaced the tstat timing belt waterpump and have flushed the system several times. But it still keeps overheating and pushing the water out of the overflow tank and this morning after sitting all night the system was still pressurized what can be causing this and can I fix this problem