efseiler Posted April 19, 2015 Share Posted April 19, 2015 I'm a little confused as to what is referenced by an 'external leak' regarding headgaskets. Do they mean that the coolant is seeping thru the gasket into the combustion chamber? Quote Link to comment Share on other sites More sharing options...
lmdew Posted April 19, 2015 Share Posted April 19, 2015 Oil or coolant comes out of the engine at the HG. You can see it leaking at the HG splitline. Different from Internal leaks of the 96-98 DOCH engines. Quote Link to comment Share on other sites More sharing options...
nipper Posted April 20, 2015 Share Posted April 20, 2015 Head gaskets are complicated things. internally they have to seal high combustion pressures and temps, seal a water jacket at 14ps, deal with external temps from -50F to 150F. They have to deal with fast moving air, high flow water, and oil up to 80 psi. If your lucky all will work well. If not you can get an external leak of coolant or oil (which on subarus one can live with unless its driping on a hot exhaust). If you are unlucky they will fail on the combustion side. Like Imdew said DOHC tend to blow in the worst way possible. SOHC tend to weep oil or coolant. Weeping can be tolerated if you keep an eye on the fluid levels. Weeping wont strand you, a combustion side leak will. Quote Link to comment Share on other sites More sharing options...
efseiler Posted April 20, 2015 Author Share Posted April 20, 2015 I've been trying to diagnose what my Forester is doing and it's been a little difficult to nail it because sometimes the symptoms seem to disappear only to reappear. I noticed some substantial coolant contamination in the oil and thinking I was totally screwed I stopped by a local shop and they said it was the so-called 'external leak' that those Subies have and offered to redo the heads with no guarantee. I threw in an extra dose of Radweld and it seems to work... Maybe the right additive combo will seal it but figuring it out can be a difficult chemistry problem in and of itself as there are heat transfer, temperature and pressure issues along with the shear stresses and strains to consider. A recent video revealed that the boxer design does contribute to that failure as the breach occurs on the lower side of the head. The combination of friction and gravitational forces work against the gasket's integrity. I guess I if can solve that solid-state physics problem it would be worth $2200 bucks to me! There are a lot of nay-sayers out there but I bet a chemical solution is possible. It's all about getting a few drops of glue into the right place. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 20, 2015 Share Posted April 20, 2015 I noticed some substantial coolant contamination in the oil . Can you describe that a little more - did you see that in oil fill tube, when draining oil, on the dipstick, or under the engine/crossmember? Also what vehicle - 1998 Foresters have the Phase I EJ25D and 1999+ Foresters have the Phase II EJ25, those two engines have distinctly different failure modes/symptoms. "external leaks" only applies to 1999+ 2000+ (and 99 Impreza RS and 99+ Forester) factory installed HG's leak externally, the oil seeps past the headgasket and eventually drips down on the ground, rear crossmember, and/or exhaust like other fluid leaks in an engine. They can leak oil or coolant. 2005+ models being more prone to oil leaks. They get worse veeeerrrrryyy slowly over time. keep topping them off and they easily run 50,000 miles or more miles without issues. you can basically run them as long as your tolerance for checking/topping fluids and/or smoking oil off the exhaust allows. Nearly 100% of factory installed coolant leaking EJ25 headgaskets will be cured with Subaru Coolant Conditioner at onset. Oil leaks haven't found any cure, just replacement. *** Previously replaced headgaskets have varying symptoms and can exhibit overheating symptoms like the older Phase I 1996-1999 EJ25D's. 2000-2002 EJ25's had an extended 100,000 mile headgasket warranty. High percentage repair used by folks very familiar with these engines goes like this: 1. resurface the heads 2. use EJ25 Turbo headgaskets Quote Link to comment Share on other sites More sharing options...
efseiler Posted April 20, 2015 Author Share Posted April 20, 2015 Yes it's a 2001 Forester S with an automatic xmission and an EJ251. I check the vehicle after every drive practically to catch anything serious in the bud and also in the morning before I take off cuz weird paranormal stuff happens up North here in the wee hours of the morning (when we're all dead asleep). I could write a whole book about strange stuff 'it' does. Now what I notice is the oil is clean when I retire it for the evening but sometimes in the morning when I check the oil is slightly milky from coolant seepage (I guess). But it's far from clear to me how coolant seeping presumably through the headgaskets during the night could make its way all the way to the oil pan (and be thoroughly mixed, too!) It did spill a bunch of coolant during the winter onto the ground probably because it was very, very...very cold this year. So far the Radweld conditioner stuff seems to be working. I bought some Bar's oil conditioner for 5 bucks (they claim it could seal an internal leak). I haven't inspected the stuff or tried it yet. My $.02 Quote Link to comment Share on other sites More sharing options...
nipper Posted April 20, 2015 Share Posted April 20, 2015 Has your PCV valve ever been changed? Spilling coolant winter or summer is not a good or acceptable thing. Where are you seeing the milky oil? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted April 21, 2015 Share Posted April 21, 2015 So you're seeing this on the dipstick? Definitely coolant or could it be water? Are you taking a lot of short trips with this car? I think it's said that (you can google it probably) short trips can tend to contaminate oil with water. Quote Link to comment Share on other sites More sharing options...
efseiler Posted April 21, 2015 Author Share Posted April 21, 2015 This morning when I got up and checked the coolant level was back to normal...just a little high. But it was amazing to me how much of it got sucked back into the radiator! The oil wasn't really milky at all. I took it for a 50 mile drive today to take my Mum to the dentist and when I got back the coolant level in the OF tank rose even higher than the day before! There was some evidence of bubbling but it didn't seem to smell like exhaust gas. It made a weird sound a couple of times, too, once about a month ago...kind of like a rattling, thrashing sound for a few moments from a cold start. Seemed to be coming from the cylinders. Sounded like a snare drum... It also gives the same EVAP code, too, occasionally...usually on cloudy, low pressure days. Maybe the on-board 'puter really is that smart... I haven't changed or inspected the PCV valve... --Damien Quote Link to comment Share on other sites More sharing options...
efseiler Posted April 28, 2015 Author Share Posted April 28, 2015 Well a week has gone by and a Subie that I was sure was in for major repairs now seems fine, like the proverbial frozen snake thawing in the Sun and suddenly coming to life (if you've ever heard that fable...it was popular in Montana). I don't know how...but it sucks like almost an entire quart of coolant back into the radiator at night and in the morning the oil now crawls like almost a third of the way up the dipstick. So I threw the physical chemistry text out the window, bought some stock in snake oil and decided to believe in miracles... Quote Link to comment Share on other sites More sharing options...
lstevens76 Posted April 29, 2015 Share Posted April 29, 2015 Ok, you use a "variable weight" oil. This means it can contract and expand with temperature. And I thought someone already went over that coolant and water both expand when getting hot. That is why the overflow is there, to keep the pressure at the right amount but still be able to pull the coolant back in when cold. Basically as your coolant gets warm and increases pressure the cap releases that pressure into the overflow. As long as your overflow isn't leaking that coolant gets sucked back in when the car cools down. Quote Link to comment Share on other sites More sharing options...
efseiler Posted April 30, 2015 Author Share Posted April 30, 2015 And I thought someone already went over that coolant and water both expand when getting hot. That is why the overflow is there, to keep the pressure at the right amount but still be able to pull the coolant back in when cold. Well...that's what I was preaching at first...but now I'm in the choir! That theory may no longer be 'among the living'. p.s. We all had to drink our 'boos, man'. Quote Link to comment Share on other sites More sharing options...
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