jeffdpia Posted December 2, 2009 Share Posted December 2, 2009 (edited) Over on wrxnet, someone steps through the HG replacement process with pics on a 98 2.5 Forester. Is this possible on a 96 ej25 OB? History;Just had one overheat at 119k, filled rad, burped, went 25 miles home with steady temp gauge, no problem. Negative hydrocarbon radiator test, negative pressure test. Will do compression test this weekend after thermo replacement. Mech says he knows its the thermo... after 25 years blah blah blah, not the HG. BTW:Can thermostats fail by closing, and then revert to the stuck open position? Thanks all Edited December 3, 2009 by jeffdpia Quote Link to comment Share on other sites More sharing options...
idosubaru Posted December 2, 2009 Share Posted December 2, 2009 Unless the mechanic knows Subaru's very well, he is likely mistaken. Very common for a mechanic to think the head gaskets are fine when they are not, happens all the time on EJ25's. EJ25 headgaskets (at least the Phase I that you have) can be bad but pass all typical head gasket tests. Passing a hydrocarbon or compression test means very little. Mechanics not familiar with the EJ25 won't know this. Yes it's possible for thermostats to get flaky or for an aftermarket thermostat to cause issues (Subaru tstats are far more robust, even visually). You most likely have a headgasket and they're a pain to do in the car. But your DOHC 96 is identical in every way to a 98 Forester DOHC EJ25 - same engine. Quote Link to comment Share on other sites More sharing options...
jeffdpia Posted December 2, 2009 Author Share Posted December 2, 2009 Thanks for the quick reply. I'll do the compression check anyway, then enlist a friend of mine who is a engine mech. to help out. I have to do the heads in the car, no hoist or extra garage space. Since its open, I'll replace timing belt, tensioner,water pump, other seals I can get to. What about gasket kits, which one is best? Quote Link to comment Share on other sites More sharing options...
mdjdc Posted December 2, 2009 Share Posted December 2, 2009 Hey, If you want, just limp that thing down to Richmond one weekend and we can do the job in my workshed. (I'm assuming that you are in Herndon , va.) I have access to all the necessary tools and the engine lift and and engine stand. If you come down early enough,we can have it done in one day. I've done many of these, so it is old hat now. Let me know if you have access to the proper headgaskets. I can get them for around 33.00 each. While you are at it you should do the timing belt and water pump too. Let me know if I can help. Quote Link to comment Share on other sites More sharing options...
jeffdpia Posted December 2, 2009 Author Share Posted December 2, 2009 Ya know, I might just take you up on that offer, but first let me compression test it this weekend. Also noticed while I was under that I need to replace a front drive shaft. So I'll probably do that this wknd, nope...scratch that... I have to replace some ceiling drywall due to a minor kitchen flood (yikes). When it rains, it pours, literally at my place. Thanks for everyone's help here, great board, great people! Quote Link to comment Share on other sites More sharing options...
mdjdc Posted December 2, 2009 Share Posted December 2, 2009 Head gasket failures on these are a weird bird. your compression test will most definitely come up normal. They leak into the cooling jacket and cause the coolant to overheat and then boil out of the rad. Then the car starts to everheat and that is what you see on the temp guage. As I said, I've done several of these and other mechanics have been at a loss as to how a car with goo HG's overheats, when in fact, the HG's are bad, but only mildly so. Don't wait too long. We can do the axle at the same time we are doing the HG's. As long as the axle isn't making any noise, I wouldn't worry about it, it will last until you can get down here. Cheers Quote Link to comment Share on other sites More sharing options...
torxxx Posted December 2, 2009 Share Posted December 2, 2009 You need to do get a block tester and use it on the radiator. If the dye turns yellow, u got bad HG's. compression test rarely shows a bad HG on a subaru. Do your self a favor and pull the engine out. An EJ25D is a very hard engine to work on in the car. Change the spark plugs and then tell me u wanna attempt HG's in the car. You can have the engine out on the floor in under an hour. From there you are looking at maybe 2 hours pulling the heads off. make sure you mark the lifter caps and that they go back in the same hole they came out of. If you dont you are gonna have a big problem with ticking and a possibility of a valve not closing all the way. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted December 3, 2009 Share Posted December 3, 2009 first let me compression test it this weekend. that'll turn out within spec i can tell you with 100% certainty. a fine thing to try but those spark plugs make it a real annoying job. good luck. dont' know if any coolant has ever been drained or lost from this car but keep in mind these cars are notorious for overheeating if you don't get all the air out of the system. in others words if a hose was replaced or removed, it's going to overheat just because there's air in the system unless you bleed or "burp" it properly. very common cause of overheating that happens any time coolant is lost. Quote Link to comment Share on other sites More sharing options...
jeffdpia Posted December 3, 2009 Author Share Posted December 3, 2009 So last nite, I changed the thermostat and cap (rubber was definitely old), rad fluid, cleaned out the reservoir (not terribly oily or sooty, 13 years accumulation), refilled, burped, drove , cooled, burped gain, changed oil. Drove to work this morning, 12 miles, stop n' go, up to 45, AC on, temp gauge steady. I know what you're thinking...fool, it's just gonna happen again. Hey Mdjdc, my wife agreed to follow me down so she could go museum hopping, while you and I rip up the OB. I feel the HG's will go anyway, any one hear of them lasting??? If I read any more bad news, I'm switching to the DisneyFantasySubaruLovers board...Thanks all Quote Link to comment Share on other sites More sharing options...
idosubaru Posted December 3, 2009 Share Posted December 3, 2009 any one hear of them lasting???of course, it's kind of silly to think 100% of an engine, or transmission has the same exact problem. well except maybe american cars - like the dodge neon. 150% of those have head gasket problems:lol: Quote Link to comment Share on other sites More sharing options...
mdjdc Posted December 3, 2009 Share Posted December 3, 2009 Just let me know what weekend you want to come down. I know that next weekend is out, but there is time coming up that I have free. Pm me and we can get the timing down. Mike Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted December 3, 2009 Share Posted December 3, 2009 For what it is worth, others have made trips with known bad head gasket, by simply loosening the vent screw on top of radiator at opposite end from rad cap. Loosening the screw vents exhaust gas in cooling system, allowing the gas to escape in the air. This prevents the cooling system from pressurizing properly, but it will help keep the engine from over heating. Quote Link to comment Share on other sites More sharing options...
jeffdpia Posted December 3, 2009 Author Share Posted December 3, 2009 Maybe in an emergency sit you would go unpressurized, but the engine would get smokin' hot, with the coolant sprayin out like the Bellagio fountains. I've got one overheat, maybe just due to the original 13 year old thermostat and cap. 50 miles later, after new parts, no smells, leaks or level loss. The HG's are gonna get replaced anyway, like I said, the stars are aligned to getr'done this month. An early Subaru Christmas present... Quote Link to comment Share on other sites More sharing options...
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