i have a 98 forester that overheats randomly.i put a thermostat in it but still overheats.

IMO this sounds like a head gasket going south on you. You can reads a lot about this on this forum by reading the archives on this website. This is a common problem with Subies with your 2.5 litre engine.

IMO this sounds like a head gasket going south on you. You can reads a lot about this on this forum by reading the archives on this website. This is a common problem with Subies with your 2.5 litre engine.

After i posted i found lots of info. the thing that gets me is i can drive it for a couple hundred miles or only 50 miles in between these overheating attacks.would'nt a head gasket run hot all the time

HG failure is not uncommon w/ the early 2.5 engines. However, you might want to first make sure you don't have air in your coolant system. I had a 95 a few years ago with a 2.2 that kept overheating at random times after two thermostat replacements by me. Coolant level looked normal. I was new to subaru and clueless. Someone here suggested I "burp" my coolant system and, sure enough, it worked out some air and I then added the fluid to top off the system and never overheated again. High temps with an alum engine makes me nervous...

After i posted i found lots of info. the thing that gets me is i can drive it for a couple hundred miles or only 50 miles in between these overheating attacks.would'nt a head gasket run hot all the time

 

 

 

Strange as it may seem, the random over heating is very typical of a head gasket going bad. IMO, you will have to repair the head gasket, because the over heating attacks will get more and more frequent. Suggest not driving your car in a state of over heating. To do so, will completely destroy the engine.

 

One easy way to verify that a head gasket is bad, is to look for bubbles in your radiator over flow tank during an over heating episode. Bubbles are exhaust gas that is entering the cooling system causing the over heating.

the thing that gets me is i can drive it for a couple hundred miles or only 50 miles in between these overheating attacks.would'nt a head gasket run hot all the time

here's the distinction - that is odd for other motors...EVEN OTHER SUBARU motors. but it's completely normal for the EJ25 to do this. very common. it's a 2.5 liter subaru specific symptom.

 

but first, before deciding on a huge repair, make sure. it could be as simple as an air pocket. this would be most likely if some recent work was done just prior to the overheating - water pump, radiator, coolant flush, radiator cap...anything coolant related. or i guess it could have randomly gotten low, but i doubt it.

 

anyway - check for air bubbles in the reservoir, that's a sure sign of head gasket issues.

 

look here for all your Ej25 head gasket needs - these motors confuse many mechanics. they fail oddly (as you've found), they can pass compression tests just fine with a blown head gasket, and can even pass the exhaust gas in the coolant tester as well. many of us on here are very familiar with the EJ25 head gasket.

Ditto on the last 3 posts, I had 2 did excatly the same thing. It's how these go south. Keep driving it, eventually it'll overheat all the time. Alum. stop leak worked for me for about a year, but they all go given enough time and driving.

Ditto on the last 3 posts, I had 2 did excatly the same thing. It's how these go south. Keep driving it, eventually it'll overheat all the time. Alum. stop leak worked for me for about a year, but they all go given enough time and driving.

thanks for the info.My only question now is if I want to repair this engine or swap to a 2.2It has 164,000 on it.I'd like to see how many miles I could get out of it. Joe

IMO this sounds like a head gasket going south on you. You can reads a lot about this on this forum by reading the archives on this website. This is a common problem with Subies with your 2.5 litre engine.

Thanks for the info. Joe

thanks for the info.My only question now is if I want to repair this engine or swap to a 2.2It has 164,000 on it.I'd like to see how many miles I could get out of it. Joe

you just have to weigh the cost of the repair against the potential miles you can get out of the engine. 1000$ for a 2.2L engine swap, (parts and labor) is probably a safer bet than 1200 - 1500$ on a 2.5L engine with 164k.

 

the labor difference is the gasket job. the engine R & R is the same for both. the gasket & t-belt parts may be the same as the 2.2L engine cost, with the 2.5 you 'will' do the timing belt and related parts since a failure wil ruin the engine, and you don't want to have to go back in for 100k. with the 'right' 2.2L you "could" just stick it in, a failed timing belt will only cost you a tow more than doing it now. but by doing it now, you should get 100k trouble free miles.