1986Brat Posted August 22, 2015 Share Posted August 22, 2015 Picked up this wagon with 215k miles a few months ago, I first noticed it would very slowly overheat at idle and cool back down as soon as it got moving. I did a coolant flush, changed the thermostat, and the issue was solved... For a couple weeks. Yesterday after an hour of driving I noticed it would very slowly overheat at idle when the AC was on. Turn AC off, temp creeps back down. Today the check engine light came on. The fans are both working. It does leak a little oil at drivers side rear part of the head gasket (maybe a quart between oil changes if that). I kind of expected I would end up changing a head gasket when I purchased a subie with 215k miles lol. It doesn't appear to leak any coolant, however. Any ideas? Has my head gasket job come sooner than anticipated? Thanks. Link to comment Share on other sites More sharing options...
montana tom Posted August 22, 2015 Share Posted August 22, 2015 An 02 with 215K could have a poor flowing radiator. Also only a subaru thermostat is reliable. Rad cap is another cheap thing to try. Link to comment Share on other sites More sharing options...
Rooster2 Posted August 22, 2015 Share Posted August 22, 2015 An 02 with 215K could have a poor flowing radiator. Also only a subaru thermostat is reliable. Rad cap is another cheap thing to try. +1 on Montana Tom's advise. Doesn't sound like a head gasket issue. I think I would be more inclined to replace the thermostat first. Install an OEM thermostat, parts store or on line purchase. You need to spend at least $30 to assure that you have bought a good thermostat. The parts store cheapies cause just the problem you are having right now. Link to comment Share on other sites More sharing options...
1986Brat Posted August 22, 2015 Author Share Posted August 22, 2015 The thermostat I got cost around 25 bucks... They said it was "OEM" as is same temp as original but it is the German company whose name doesn't come to mind... Stant maybe? People before me used aftermarket thermo, the OE I got was much larger in size. radiator cap looks fine but I guess I'll change it, sure would be nice if that was the issue. Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 23, 2015 Share Posted August 23, 2015 stant does make a t'stat that seems to be built to OEM specs. just avoid the tiny style; sure all the rad fans were working? some people report that can get intermittent with age. Link to comment Share on other sites More sharing options...
ocei77 Posted August 23, 2015 Share Posted August 23, 2015 Stant #48457 is the one you want. It's called Xactstat. O. 1 Link to comment Share on other sites More sharing options...
Rooster2 Posted August 23, 2015 Share Posted August 23, 2015 Take off the rad cap. Do you see gunk in and around the rad cap, and inside the rad opening. If really dirty with gunk, it is an indicator that the radiator system was not maintained very well. That build up of gunk can lower the performance of the radiator. If so, you may need to have the radiator cleaned, or replace it. Link to comment Share on other sites More sharing options...
1986Brat Posted August 24, 2015 Author Share Posted August 24, 2015 The Stant 48457 is the thermostat I have in it. It overheated again today, way faster than before... Waited for it to cool and blasted heat all the way home. Looks like I'll be driving the Brat this week. I think I'll just pull the thermostat out and see if the problem persists. Also, the radiator cap was perfectly clean, gaskets look good, seems to work fine. The coolant I put in roughly 2 weeks ago is still really clean, radiator looks okay. Link to comment Share on other sites More sharing options...
Rooster2 Posted August 24, 2015 Share Posted August 24, 2015 Another thought, it could be a problem with the water pump. I read a story once about a guy with over heating problems. Turned out to be the water pump. His had plastic impeller vanes that had broken off, and so was not pumping the coolant through the system very well at all. I think the car was a BMW, so don't know if that could ever be a problem with a Subie. Link to comment Share on other sites More sharing options...
1986Brat Posted August 24, 2015 Author Share Posted August 24, 2015 Well if the problem persists after I remove the thermostat, I think it would be safe to say that the water pump is the issue. Does this sound reasonable? Also, would it be fine to drive without the thermostat for a week or so (assuming it stops overheating)? It normally hits 90 degrees every day around here so I don't think I'd have an issue getting up to operating temperature. Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 24, 2015 Share Posted August 24, 2015 when it overheats, is fluid being pushed into the coolant overflow tank? If so, headgasket leak is suspect. I think a radiator can be flow tested at a rad shop. Or, maybe scan it for cool spots with an infrared thermometer. Link to comment Share on other sites More sharing options...
1986Brat Posted August 24, 2015 Author Share Posted August 24, 2015 Yes, the coolant level in the reservoir becomes mostly full when it overheats... Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 24, 2015 Share Posted August 24, 2015 probably headgaskets then - combustion pressure is getting into the coolant. there is a head gasket test you can get at the parts store - some people have luck with it - works best if the there is active bubbling coming through the o'flow tank or radiator. you can find youtube videos for it. Turns a blue liquid green I believe. not good news - maybe I'm wrong and you just need to burp the system better but - that is typical HG failure symptoms for LOTS of subarus with bad HGs. Link to comment Share on other sites More sharing options...
1986Brat Posted August 24, 2015 Author Share Posted August 24, 2015 Ah guess I'll pick up a test kit then. Link to comment Share on other sites More sharing options...
1986Brat Posted August 27, 2015 Author Share Posted August 27, 2015 So I decided to try burping the cooling system before doing anything else, and sure enough, lots of air had gotten into the system. I let the vehicle run for over an hour and found that every 10 minutes or so I was able to get more bubbles out by squeezing upper and lower rad hoses. When I stopped burping it and let it run, I found that the coolant level would very slowly rise as the air built up in the system. This explains why the coolant level in reservoir while cool gradually increased over the period of 2 weeks since coolant flush. oh and yes the thermostat clearly opens when fans kick on. Anyways the burping Temporarily solved the issue but I'm assuming those are combustion gases from failing head gasket slowly building up in radiator and I'll have to burp it every 2 weeks or so to keep it cooling properly. Link to comment Share on other sites More sharing options...
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