I've been going completely crazy trying to figure out what's wrong with the cooling system in my '97 Legacy Outback . It keeps overheating even though I've replaced the thermostat , checked all my hoses , coolant and fans . Everything seems to be in working order . Any ideas of what the problem may be ? I sure would appreciate any feed back you may have .

[...] It keeps overheating even though I've replaced the thermostat , checked all my hoses , coolant and fans . [...]

Under what conditions does it overheat?

 

Do a search for "head gasket" on this forum and see if the symptoms of bad ones seem familiar.

It overheats under pretty much every condition . After 15 minutes of driving the gauge just jumps up to high . It can sit and idle for a long time and won't overheat , but when I start driving it does . Thanks for the heads up on the head gasket , I'll look into it . Thanks

Seems like no one uses the search function.

 

1. did you use a Subaru thermostat? Aftermarket ones can cause problems. Have you replaced the rad cap with a Subaru one? Did you get all the air out of the cooling system? Are you checking the coolant level in the rad (cold) or just the overflow tank?

 

2. If you used an aftermarket thermostat is it installed backwards?

 

3. Is your heater core plugged? You can bypass it with a couple of elbows and some heater hose as a temporary solution. Restricted heater core prevents the thermostat from opening properly.

 

4. Is the rad restricted?

 

5. do you have bubbles in your overflow tank? Does your over flow tank overflow?

 

Under what conditions does your car overheat?

 

Overheating is a common occurrence on some older Subaru's, try searching for overheating. You'll get lots of threads to read.

5. do you have bubbles in your overflow tank? Does your over flow tank overflow?

 

 

it could be any of the things mentioned above but if you have this one i would not spend a lot of time checking the others. these engines have a history bad head gaskets.

 

read this to better understand the problem:

 

http://www.ultimatesubaru.org/forum/showthread.php?t=104353&highlight=overheating+head+gasket*

Edited March 20, 201016 yr by johnceggleston

I suggest you get a block check done to see if exhaust gases are getting into the coolant. If that checks out ok then I would suspect the radiator is clogged and a replacement is needed.

!st, how did you fill the cooling system You may have a air pocket in the cooling system.

 

If not then Head Gasket. Clogged raditor would overheat or run hot depending on load, OP says it is always overheating.

I checked EVERYTHING and replaced the thermostat (again) , the coolant temperature sensor , burped the rad , which purged large amounts of air and somewhere solved the problem . Thank you for your help !