CFab Posted October 21, 2014 Share Posted October 21, 2014 So I had replaced the thermostat the first time and a couple of months later it was overheating again- usually after it had been running off and on that day. short 10-20 minute trips. doing fine, then temp gauge shoots up and it doesnt come down till I turn it off. The heat might not work as well. Ive burped it by the manual a couple of times since the 2nd thermostat (from Subaru- amazing how much better it is). It is doing it again. It doesn't seem super hot- there is no steam and it smells ok. the radiator may be hot or it may be warm. I may keep the fans running and it'll cool down pretty quickly. burp it again and it does it again. no leaks of coolant or oil as far as I can tell. ANY IDEAS(besides head gasket)? 1 Link to comment Share on other sites More sharing options...
Twitch de la Brat Posted October 21, 2014 Share Posted October 21, 2014 So I had replaced the thermostat the first time and a couple of months later it was overheating again- usually after it had been running off and on that day. short 10-20 minute trips. doing fine, then temp gauge shoots up and it doesnt come down till I turn it off. The heat might not work as well. Ive burped it by the manual a couple of times since the 2nd thermostat (from Subaru- amazing how much better it is). It is doing it again. It doesn't seem super hot- there is no steam and it smells ok. the radiator may be hot or it may be warm. I may keep the fans running and it'll cool down pretty quickly. burp it again and it does it again. no leaks of coolant or oil as far as I can tell. ANY IDEAS(besides head gasket)? Either you have a nasty air bubble in your heater core, a clog somewhere or, well, I have some bad news for you... Twitch Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 22, 2014 Share Posted October 22, 2014 What year? Link to comment Share on other sites More sharing options...
idosubaru Posted October 22, 2014 Share Posted October 22, 2014 this: What year? sounds like a 1998 Forester or a later one that's already had the headgasket replaced or abusively overheated. Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted October 22, 2014 Share Posted October 22, 2014 is it pushing coolant into the overflow? If so, given your other info - almost certainly headgaskets. Link to comment Share on other sites More sharing options...
Rooster2 Posted October 22, 2014 Share Posted October 22, 2014 Yea, classic behavior of bad head gaskets. Link to comment Share on other sites More sharing options...
Dinky26 Posted October 23, 2014 Share Posted October 23, 2014 My nephews 99 Forester is filling the overflow then pushing onto the ground. Doesn't seem to be overheating or I don't think so, I guess I can't really say for sure 100% since I haven't been driving it. I did replace the radiator on the diagnosis from a shop that said the radiator needed replaced. And it continues to do the same thing. Any other way to tell if the HGs are toast? Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted October 23, 2014 Share Posted October 23, 2014 (edited) there's a iffy chemical test available from parts stores - even some youtube videos showing how it works. you could ask blackstone labs or polaris labs about a fluid analysis. I think some people have confirmed with an overnight coolant system pressure test. A shop with the old-style tailpipe emissions probe might be able to detect combustion products in the radiator. Edited October 23, 2014 by 1 Lucky Texan Link to comment Share on other sites More sharing options...
ThosL Posted October 24, 2014 Share Posted October 24, 2014 (edited) there's a iffy chemical test available from parts stores - even some youtube videos showing how it works. you could ask blackstone labs or polaris labs about a fluid analysis. I think some people have confirmed with an overnight coolant system pressure test. A shop with the old-style tailpipe emissions probe might be able to detect combustion products in the radiator. It depends how bad the head gaskets are, I have had at least short term success with "Blue Devil" and "Fiber Lock" (a three-pronged approach) which run around $70 and $35 each with guarantees--keep all receipts and original packaging if it doesn't work as they can be hard to get money back on otherwise though I have been able to do that. Other thoughts on keeping the engine cool; there are super cooling fluids to add, a secondary radiator maybe, an extra fan. I have even put the heater on full to suck heat out of the engine. If it turns out to be you need to get the head gaskets replaced, parts alone could be $400 according to a worker at NAPA I was talking to today who had her husband a mechanic do the job including pump and timing belt. I would look at all options, check out the videos on you tube with all the critical comments!! You don't want to clog up your cooling system. Edited October 24, 2014 by ThosL Link to comment Share on other sites More sharing options...
turbosubarubrat Posted October 24, 2014 Share Posted October 24, 2014 While the heads are off you should have them resurfaced and have the leaking valves ground or all ground. A set of my heads are getting resurfaced and 3 valves ground for $180. I'm only doing the 3 since none of the others leak from the test so why fix something that ain't broken. Plus it would cost $310 for a resurface and all 16 valves ground not including if you have a bent or burnt valve which are a little over $10 a piece. Link to comment Share on other sites More sharing options...
Vermontsailor Posted October 28, 2014 Share Posted October 28, 2014 This stuff is contagious...I have 2008 Forester X that was head gasketed 30,000 miles ago. I am in complete Hamlet mode: "...to do, or not to do, the head gaskets: that is the question..." as this the engine has 235,000 and in April had an overheat, then again in August, then two weeks ago. Topped off and burped each time, new Subaru thermosta. And now: Builds up tremendous pressure in the system - the last overheat it blew the top hose off. Radiator appears to be leaking. Car sputters when I step on the gas and I have fault code lights on - am scanning them today on the odd chance that this is all about a bad sensor - which I strongly doubt. Then it dies. Does not appear to be losing coolant at this point (?) So - is this a head gasket or something else? TIA, O.P. Link to comment Share on other sites More sharing options...
lmdew Posted October 28, 2014 Share Posted October 28, 2014 HG most likely. The high pressure is combustion gas leaking into the coolant. bubbles in the overflow tank. I picked up a 98 that blew coolant about 30' in the air when I started the engine to finishing filling the radiator. Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 28, 2014 Share Posted October 28, 2014 Builds up tremendous pressure in the system - the last overheat it blew the top hose off. That sounds like a major head gasket leak. Link to comment Share on other sites More sharing options...
Dinky26 Posted October 30, 2014 Share Posted October 30, 2014 Yeah, I'm in the process of tearing it down to replace the HGs. Got the intake off and the passenger side valve cover last night, didn't touch it tonight, resting my hand after having really HOT coffee spilled on it. .ugh. . Tomorrow I'll hit it again. Ordered a straight edge to check the block. $80 later I have one on the way. . Ouch..... Link to comment Share on other sites More sharing options...
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