Wayne Boncyk Posted June 4, 2006 Share Posted June 4, 2006 Well, I guess I shouldn't be surprised - with more than 216,000 miles on my 2.5L (in a '96 Outback Wagon), I'm starting to see some evidence of excessive blow-by. But interestingly enough, the tell-tale blue cloud out the exhaust is only showing up after prolonged periods of "compression braking." I took a drive up (and down) Trail Ridge Road yesterday, just because I haven't been up there in decades and I wanted a nice cool drive in the high country to escape the 90+ degree Fahrenheit heat down in Denver. The day was grand, the trip up was beautiful, but the trip down was marred by a dude in a mega-box SUV (Lincoln Navigator, I think) who must have been from Kansas or Nebraska or somewhere like that. I doubt if he's ever before been on a hill with more than 1% grade. He was white-knuckled all the way down the mountain, and we descended at an average speed of about 12 mph. Along with driving me and everyone else behind him absolutely nuts (he didn't have the presence of mind to pull into a turn-out so he ended up with about 50 cars in a long procession behind him), he caused me to do most of the descent in 2nd or 1st (I have a 4EAT in the OBW). When I finally got the chance to step on the accelerator again (instead of the brake), I fumigated the rest of the line of cars behind me. To anyone who was there, sorry about that!! I give you the whole story only because this is the ONLY time I've ever seen visible evidence of smoking thru the tailpipe in this car, except for a little that was associated with the Head Gasket failure that I fixed back at 160K miles. And since I just got back to Colorado about a month or so ago, I had to run the beast through the state emissions test (which includes a full 4-wheel dyno acceleration profile test) and we easily passed. So, I figure that the rings are still in pretty good shape for an engine this old. I will of course do a compression and leak down later -- when all my tools and equipment get moved out from California at the end of this month -- but until then I'm wondering if there is anything I can do (additives or otherwise) to minimize the problem until I can fully diagnose it. Like I said, it sure looks like ring blow-by to me, but all other opinions (and suggestions for potential fixes) are welcome. And for those of you who don't know, Trail Ridge Road is the highest paved road that crosses the Continental Divide anywhere in North America. The highest point is at roughly 14,000 feet (4265 meters) above sea level, and even on the hottest summer days in Denver it is a refreshing 40-50 deg. F up there! Almost always a cool ride -- although I think I'll skip going up there on weekends from now on! Quote Link to comment Share on other sites More sharing options...
nipper Posted June 4, 2006 Share Posted June 4, 2006 im going to say dont worry about it. It sounds like valve guides or stem seals, and since it happend under an extreme condition. im going to guess its the stem seals. i really think you have nothing to worry about, as the stem seals do go eventually even in the best of homes. When you fixed the headgasket did you do any valve work? nipper Quote Link to comment Share on other sites More sharing options...
Monte Posted June 4, 2006 Share Posted June 4, 2006 I remember this from my Chevy 235 days. I think it's rings. It'll start doing it eventually just compression braking on the hiway. I think the compression rings start letting more oil stay on the cylinders because when compression braking they aren't sealing against the cylinder as tightly so they don't wipe all the oil off. Hit the gas and poof, the oil goes up in smoke. Monte Quote Link to comment Share on other sites More sharing options...
nipper Posted June 4, 2006 Share Posted June 4, 2006 rings on acceleration, valves on deceleration. Thats the rule of thumb (assuming the pcv system isnt clogged). nipper now about that funny green smoke Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted June 4, 2006 Author Share Posted June 4, 2006 nipper - valve guides/stem seals were replaced, and I made sure that the heads were lapped (to make sure they were flat) when I pulled 'em prior to replacing the HGs. And the blue puff occurs on acceleration. But, and this is why I wasn't 100% sure it was rings, it only happens after a long interval of compression braking, where there's a lot of high compression with the opportunity to push oil out everywhere, and no real "oomph" from cylinders firing, since they're basically being given an idle charge of fuel out of the injectors while my foot is completely off the accelerator on the way downhill. I guess all will be made clear when I do my compression tests, but for the time being I suppose I can just dump a quart of Lucas Stabilizer or other viscosity increaser into the crankcase to keep from blowing off too much oil. Unless you guys know of something that works better than Lucas.... Also, I'm gonna check the pcv valve right now. It may be gummed up since I don't remember checking it the last time I changed oil. Quote Link to comment Share on other sites More sharing options...
nipper Posted June 4, 2006 Share Posted June 4, 2006 nipper - valve guides/stem seals were replaced, and I made sure that the heads were lapped (to make sure they were flat) when I pulled 'em prior to replacing the HGs. And the blue puff occurs on acceleration. But, and this is why I wasn't 100% sure it was rings, it only happens after a long interval of compression braking, where there's a lot of high compression with the opportunity to push oil out everywhere, and no real "oomph" from cylinders firing, since they're basically being given an idle charge of fuel out of the injectors while my foot is completely off the accelerator on the way downhill. I guess all will be made clear when I do my compression tests, but for the time being I suppose I can just dump a quart of Lucas Stabilizer or other viscosity increaser into the crankcase to keep from blowing off too much oil. Unless you guys know of something that works better than Lucas.... Also, I'm gonna check the pcv valve right now. It may be gummed up since I don't remember checking it the last time I changed oil. One of the good or annoying things about oil, is that it doesnt take much to make a lot of blue smoke. The only time you really fail an emisson test for burning oil is if you are making an obscene amount of smoke. Usually that much oil will foul the cat. A cat can withstand a quart per 600 miles (the old standard thats used as excessive oil burning). If your not seeing it on your dipstick, i still wouldnt sweat it that much. My car burns oil only in the winter and the first start of the day (and yes it bothers me). When i did have an oil burner i used the STP, but thats just personal preference. Compression test will be interesting to see the difference between wet and dry numbers. nipper Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted June 4, 2006 Author Share Posted June 4, 2006 Yup. Can't wait until I can move my stuff out here. BTW - How're you doing? Are you able to work on your own vehicles again? I seem to remember you were laid up a few weeks ago.... Quote Link to comment Share on other sites More sharing options...
nipper Posted June 4, 2006 Share Posted June 4, 2006 Guess its time for an update. Still rcovering from the back surgery. i put in the accesory power outlet and it took me two days (should have been an hour tops). Physical Therapy 3x's a week. My PT said to write off this year as far as activity, since so many of my muscles are atrophied and need to be re taught. There is a paralized muscle in my left leg. We dont know if its going to come back, but i wish it would unlock. Its the muscle you need to bend your leg put your shoes on. It is also used for side to side stability. i can stand about an hour, walk for about 2 blocks i can walk a flight of stairs, which everyone seems to be shocked atGoing to be a long boring summer. Annivesary of the accidnet is july 1st. i'm going to have to pay somone to do my timing belt and the associated goodies this year. nipper Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted June 4, 2006 Author Share Posted June 4, 2006 Sorry that it's going to take months before you're "back." I hope you get back to at least close to where you were before the accident. I can't imagine what it must be like to be out of commission for so long. Quote Link to comment Share on other sites More sharing options...
cookie Posted June 5, 2006 Share Posted June 5, 2006 hang in there nip, I saw my friend Leo who has been through much the same over the holiday. he has moved to CA for the weather and now is starting to walk and not look like he is in constant pain. It takes time. About that pcv valve even if they don't seem gummed sometimes changing an old one improves oil loss. Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted June 5, 2006 Author Share Posted June 5, 2006 Well, guys. I did change out the PCV valve earlier today, and it has apparently had an effect on the oil blow-by. Maybe it wasn't ring blow-by. Maybe it was a valve stuck partially open that was sucking oil into the intake manifold. I don't know for sure yet since I wasn't gonna take another extreme drive (like Trail Ridge Road), but I did head up into the high country and did about 30 miles up and down hills, engine braking on the way down, and I noticed no blue puffs when I accelerated at the bottom of the hills. The problem may be solved -- I'll keep a watch on it for the next couple of weeks. Oh, since there were no Subie dealers open today (Sunday), I used a Fram aftermarket replacement. I'll switch over to a genuine Sube part at the first sign of something flaky.... Thanks for the hints! Quote Link to comment Share on other sites More sharing options...
brus brother Posted June 5, 2006 Share Posted June 5, 2006 OK, I generally agree with Cookie so, despite my medical training, I would reluctantly try the PCV valve to see if it helps Nipper's paralyzed muscle. Keep smiling, Nipper, laughing and crying is the same release. We're all rooting for ya'. hang in there nip, I saw my friend Leo who has been through much the same over the holiday. he has moved to CA for the weather and now is starting to walk and not look like he is in constant pain. It takes time.About that pcv valve even if they don't seem gummed sometimes changing an old one improves oil loss. Quote Link to comment Share on other sites More sharing options...
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