I have a 1996 Subaru Legacy 2.5 L EJ25D that overheats when the thermostat is in place but doesn't when the thermostat is not in place. The coolant seems to be forced into the overflow tank and usually cool not hot, the upper hose running from the engine to the radiator is really hard and really really hot the radiator itself tends to be relatively cool. The thermostat is new and it is from Subaru the coolant is Subaru coolant, there is no smell of exhaust in the Coolant just sweet smelling like it's supposed to, and there are no bubbles in the overflow tank. However I can't seem to get more than 10 minutes away from the house without it overheating these days. Any and all suggestions are welcome thank you very much have a good day.

Unfortunately, an all too common plight for this engine. You have classic symptoms of bad head gaskets. Multiple overheating cycles usually leads to rod bearing damage. If the temp needle has been to the red more than once, consider it a boat anchor now. Time for an engine swap or a complete rebuild.

what he said - sounds like headgaskets, a very common issue with that motor.

 

overheating is just about the worst thing you can do to your engine, next to running it without oil.

 

if it runs fine without the thermostat in place - leave it out.

 

normally when the headgaskets fail on this particular motor pulling the thermostat doesn't help. so i suspect either it's a very early stage of failure and it just hasn't happened to overheat yet without the t-stat, but will in due time. or yours has already been replaced before you owned the vehicle and is having a non-traditional failure.

 

the only way it could be "caused" by the tstat is if the tstat has failed.

Is the lower radiator hose hot or barely warm when the temp starts to rise?

 

O.

headgaskets or water pump seized

The bottom hose is barely warm when this happens. I don't know if it helps anything but I don't let it peg out at the H, I turn it off before it gets a chance to hit all the way, I don't know if that helps keep the motor from getting worse or not.

Water pump.

If close to t belt time, might as well replace all. (T belt, idlers,pump and check and reseal oil pump)

 

O.

is your thermostat upside down? lol water pumps never hurt

No it not backwards, my boyfriend and his dad ended up drilling 4= 5/32 holes in the thermostat and reinstalling it. So far 300 miles and no issues it maintains a steady temp and does not drop to nothing on the freeway.

if its fluctuating more than the center icon than you still have an issue....did you test the thermostat in boiling water? is your radiator cap OEM? those never hurt either. PLEASE go get some subaru coolant conditioner!!!! its made for the 2.5 engines and there head gasket "tendencies" it should only cost you $2 from the dealer and has metal flakes that seal off small head gasket problems before they get large. at worst it wont do anything at best it could keep your head gaskets from failing completely, subaru recommends using it with every coolant change.

 

http://www.fcpimport.com/products/subaru-oem-coolant-system-conditioner-soa635071

 

I have had my share of coolant wowes with my 96 lego:popcorn: best of luck hope at least some of this helps

My 2.2 recently overheated due most likely to thermostat. I let it cool for over an half hour, fluid level dropped significantly, I added coolant, no more problems. Thermostat sticks occasionally. All the things that go into keeping the engine cooler should be employed. You can even put the heater on full blast which may draw out heat temporarily in a pinch. Since it often costs over $1500 for a rebuild or replacement, do everything you can to save the engine.