Overflowing Coolant Reservoir

[BustedKnuckles1122]

Hey fellas,

Im afraid of the responses to this because I have an idea what it is. Just wanted to get 2nd opinions/confirmation. Recently my 2010 LGT started getting close to overheating. When I checked under the hood I had evidence of coolant spay. I noticed that my reservoir was way too high. So i went ahead and changed the thermostat and burped the system after refiling. After a test drive, had the same result. So I changed the radiator cap and burped again (this time no air came out). After a test drive had the same result. When i started releasing the pressure at the radiator cap, I started getting a very excessive amount of bubble escaping from the reservoir When running (either cold or warm) I haven't seen any white smoke from the exhaust. I don't have a compression tester. But is my gut feeling right? Do I have a blown head gasket? BTW 3rd owner of vehicle. 2nd owner took good care of it, and all of my maintenances have been perfect and right on time. Even coughed up the money for the dealership to do the 90k service. Tech said the car was in excellent condition. Oh, and I'm at about 96.5K right now. Any and all help appreciated.

Thanks in Advance

[MilesA]

Many people here have seen overheating problems resolved through using the Subaru OEM thermostat and pressure cap(s). If your engine is like mine, there are two pressure caps. Note that these caps are different part numbers and not interchangeable.

 

If that does not work, you can test your cooling system to see if hydrocarbons are present (i.e. exhaust gas is getting into the cooling system). The Lisle 75500 tester costs less than $30 and NAPA sells a similar one.

[BustedKnuckles1122]

Many people here have seen overheating problems resolved through using the Subaru OEM thermostat and pressure cap(s). If your engine is like mine, there are two pressure caps. Note that these caps are different part numbers and not interchangeable.

 

If that does not work, you can test your cooling system to see if hydrocarbons are present (i.e. exhaust gas is getting into the cooling system). The Lisle 75500 tester costs less than $30 and NAPA sells a similar one.

 

I have the EJ255. Do you have any idea to the air present in the system after the test drive? Or just to get the hydrocarbon test kit?

[MilesA]

I know it probably sounds strange, but people have experienced problems similar to yours that resolved using the OEM parts. Overheating, loss of coolant and air getting into the system.

 

http://legacygt.com/forums/showthread.php/subaru-giving-me-wrong-part-number-radiator-cap-my-car-260690.html

 

These are the part number I have, you might want to check them:

 

Radiator Cap - p/n 45137AE00B

Water Tank Assembly Cap - p/n 45137AE002

Thermostat - p/n 21210AA160

 

Head gasket leaks don't seem to happen very frequently with the unmodified turbo models, at least not at lower mileages like yours. So, you could use the tester just to rule that out, but it could well be something else.

[BustedKnuckles1122]

I know it probably sounds strange, but people have experienced problems similar to yours that resolved using the OEM parts. Overheating, loss of coolant and air getting into the system.

 

http://legacygt.com/forums/showthread.php/subaru-giving-me-wrong-part-number-radiator-cap-my-car-260690.html

 

These are the part number I have, you might want to check them:

 

Radiator Cap - p/n 45137AE00B

Water Tank Assembly Cap - p/n 45137AE002

Thermostat - p/n 21210AA160

 

Head gasket leaks don't seem to happen very frequently with the unmodified turbo models, at least not at lower mileages like yours. So, you could use the tester just to rule that out, but it could well be something else.

 

Thanks man, I'll look into it. I really appreciate the help!

[BustedKnuckles1122]

It ended up being my head gaskets. Had to get the heads resurfaced, valves ground, etc.

[MilesA]

Sorry that ended up being the cause. I was hoping it would be something else.

[GTEASER]

If your engine is like mine, there are two pressure caps. Note that these caps are different part numbers and not interchangeable.

 

 

His engine is like yours, but his turbo is not. 5th Gen GT has the low mount front turbo so there is no auxiliary coolant tank on the top of the motor....so only 1 radiator cap, on the radiator.