Engine overheats after a long drive or when stuck at a traffic jam?

I've replaced the water pump, timming belt, head gaskets, fans work, had checked heads ok. New thermostat. Still overheating. Any sugestion on this problem.

1998 Forester no problems at idle or town driving but overheats when driven 20 to 30 min at freeway speed. I have replaced rad (was plugged), replaced timing belt and tennsioner (belt was loose tennsioner weak), replaced water pump and thermostat ( just hoping) nothing changed, when it gets hot heat inside car goes away and eventually starts to boil over. I have not checked head gaskets because there is no sign of trouble, no leaks, no smoke out exhaust, no missfire, engine runs very smooth. I have so much time invested in this job I don't want to give up but running out of ideas. Cooling fans work and are running when car heats up, and then starts to push out coolant. Hope sombody has seen this and give me some ideas. Thanks Mike
PS tired of looking at car with dumb look on my face and not doing anything about it so I just tested for head gasket leak NOTHING WRONG THERE EITHER HELP HELP HELP HELP HELP HELP

Have you checked / replaced the thermostat?
Good luck.
Ps (How are the brakes do you have a
low peddle?

I've got the same problem. Had heads check ok. Mine has to much pressure in the coolent system. Startes out low then goes passed 35psi. This is when the coolent comes out. Need help too. New cap too.

I just had a new radiator and hoses installed. The tempreture is acting strangly now. The temp will be normal for awhile then quickly will rise into the red zone. By quickly I mean within 30 seconds. I pull over and shut the engine off for two minutes. WHen I restart, the temp is a little below the red zone. As I begin to get back onto a road and drive, the temp will quickly drop down to normal. Again by quickly I mean 30 seconds. How can the actual temp go up and then back down so fast? I had the theromstat replaced with no effect on this over heating issue. I think it might be a bad guage but it was working fine before I had the radaitor replaced. I don't want to assume that the guage is wrong and drive around without a working temp guage.

Has the thermostat been replaced with a genuine subaru part? This is a real common issue when aftermarket t-stats are used. You had also stated that other repairs were done as well. I think your main problem is the t-stat and that there is air still trapped in the cooling system.

My vehicle has been overheating off and on for about a month. I have drained and flushed the cooling system and installed an aftermarket thermostat. Then I installed an original Subaru thermostat then it ran well for a week. Then it started overheating and I was told to drill extra holes in thermostat and bleed air which I did. That made my vehicle run well for a week and now the temperature gauge needle will go to hot for a few seconds and back to normal and keep repeating. The engine does not seem to be overheating. Could this be a sensor or gauge problem or head gasket?

So I just bought a subaru forester and it has overheated twice in the past month. Both time I have been ideling and both time when I drove about 300 yards it immediatly went down to half way (which I assume is normal). The coolent level has remained the same and looks a little dirty. What say ye?

How do you check the temp sensor and relay?