Thermostat or Head Gasket?

[Sewoolf@ptdprolog.net]

 

My Subaru Legacy 2.2 Turbo has 197000 miles on it. Over this past winter I started having problems with the heating system. it would blow cool air when at an idle but blow hot air once i started moving and the engine ran at a higher RPM. Sometimes I noticed the coolant guage going up to about 3/4 but it would come back down again after I revved up the engine and drove.

 

I initially figured this was a thermostat problem. Then, the other day, I drove my usual 40 minute commute from work to home. I hopped in the car about five minutes after getting home and got on the highway for another trip. Well, my car started bucking and sputtering as if i was running out of gas or having an electrical problem. The engine also made some weird noises. I pulled over at a gas station and noticed smoke billowing out from the engine. I popped the hood and found something smoking directly to the passenger's side of the engine, next to the head and near the turbo. I'm not sure if it was oil or coolant but i am concerned something blew out. the car did start right up again and has been running ok except taht the temp guage for the coolant has been rising to 3/4 quite a bit and then coming down again. I plan on replacing the thermostat this weekend but i am worried that it is too late to prevent major damage. it has been a great car and i'd hate to give it up. Please help!

[nipper]

First of thats GREAT miles on a turbo motor. The heat issue is indictative of a HG problem. If you have an external leak, out a can of sooby coolant treatment in it. If its internal get a exhaust test for the engine coolant, or remove the radiator cap and look for bubbles.

 

 

nipper

[Sewoolf@ptdprolog.net]

There is definitely a leak somewhere. My coolant reservoir was empty but only took about 2 pints to fill. There are no bubbles coming through the system and the temp stayed steady at 1/2 last night when i took it for a test drive (after filling the coolant). There are no visible, steady leaks that I can see. I'm still guessing the thermostat is bad but working intermittantly. I'm still going to replace the thermostat. I'm wondering if a new gasket is needed for the thermostat housing? I got an o-ring seal but haven't found anything for the housing at the local auto parts store.. I hesitated to take it apart because of this. I'm also wondering what the best way to replace the coolant is in order to avoid air pockets in the system.

[idosubaru]

fairly certain the Ej22 just has the rubber seal on the thermostat housing.

[nipper]

YOu can have somone do a due test to find the leak. They but dye in the coolant then use a black light to trace the source.

 

nipper

[Subarian]

The O-ring goes on the thermostat, and then the thermostat goes into the outlet housing. There's no other gasket.

[Setright]

Before you tear the engine apart, you might as well fit a new radiator cap (yours may have two, one on the header tank) and thermstat. YES, get a new gasket for the thermostat.

 

Search for "coolant replacement bubbles" and you'll find my way of filling these engines with coolant.

[Legacy777]

I'd suspect either the water pump or headgasket.

 

The cooling issues at low idle would be indicitive of a water pump...at least to me.....but the other issues on top of it....it very well may be a headgasket.