Blue exhaust smoke on startup
11-21-2004, 07:40 PM
#16
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Originally Posted by KLR
Bear in mind that a light film of oil in the IC pipes is typical. If you have lots of oil, turbo seals could be your culprit. Spitting out unburnt oil through the exhaust would sound more like a turbo issue (i.e., post combustion chamber problem). Most people seem to lose the HG before the other components in the head give up.
For those who have done it, if you have the head off for an HG and reconditioning, how much additional work is it to replace the turbo with a rebuilt unit at the same time? Both jobs are probably beyond my DIY capability given time limitations these days, so I've been wondering when I eventually have to do one or the other (hopefully not for a while) if it would just make sense to do both at once, save on the labor, and be done with it.
For those who have done it, if you have the head off for an HG and reconditioning, how much additional work is it to replace the turbo with a rebuilt unit at the same time? Both jobs are probably beyond my DIY capability given time limitations these days, so I've been wondering when I eventually have to do one or the other (hopefully not for a while) if it would just make sense to do both at once, save on the labor, and be done with it.
Would a turbo issue be a precombustion situation instead of postcombustion? Air is sucked in through the filter goes to the turbo blades, is accelerated by the spinning blades, goes to the pre-intercooler pipe, goes to intercooler, goes to post-intercooler pipe, goes through throttle plate and is then fed into the combustion chamber by the intake manifold. Is that not pre-combustion or am I missing something here? Bear in mind before I bought this car 18 months ago, I knew absolutely nothing about mechanics. So please be gentle with me if I'm being dense about this...
11-21-2004, 08:01 PM
#17
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You're on the ball. However, bear in mind that the turbo is propelled by the exhaust. Leaking turbo oil seals will often put oil into both the IC pipes and the exhaust. One would hope that the fact that your turbo was already rebuilt would rule out a turbo problem, but I believe that John Dietz had a leaking seal crop up on a rebuilt turbo a little while after the install, so it can happen.
Now that you've gathered some ideas from this thread, I'd suggest stepping back and doing the following:
1. Assess your situation
- Are you consuming a noticeable amount of oil? Is your consumption out of spec?
- Is your oil pressure adequate/in spec? Has it changed?
- Does your car feel down on power at all?
2. Do a couple of simple diagnostics
- Take apart the IC pipes (takes 10 minutes and a screw driver) and take a look. You should find some dampness (oil) in both, particularly the one leading from the turbo to the IC. If you have a decent amount of oil in there (i.e., more than a light coating), something is not right with the turbo. This would be particularly true in your case, since your turbo should be fresh. My 119k turbo does not leave more than a light coat of oil on the IC pipe that follows it and doesn't really put any in the other IC pipe or the intake manifold.
- Buy a compression tester or drop by a shop for a compression and leakdown test. The compression test will tell you if there is a leak past the piston rings or the valves. If there is, a leak down will let you figure out where the leak is. Your shop should do this for free or for next to nothing. If your answers in step one indicate that this is not a serious issue, I'd probably let it go until the car is next due in for service.
Now that you've gathered some ideas from this thread, I'd suggest stepping back and doing the following:
1. Assess your situation
- Are you consuming a noticeable amount of oil? Is your consumption out of spec?
- Is your oil pressure adequate/in spec? Has it changed?
- Does your car feel down on power at all?
2. Do a couple of simple diagnostics
- Take apart the IC pipes (takes 10 minutes and a screw driver) and take a look. You should find some dampness (oil) in both, particularly the one leading from the turbo to the IC. If you have a decent amount of oil in there (i.e., more than a light coating), something is not right with the turbo. This would be particularly true in your case, since your turbo should be fresh. My 119k turbo does not leave more than a light coat of oil on the IC pipe that follows it and doesn't really put any in the other IC pipe or the intake manifold.
- Buy a compression tester or drop by a shop for a compression and leakdown test. The compression test will tell you if there is a leak past the piston rings or the valves. If there is, a leak down will let you figure out where the leak is. Your shop should do this for free or for next to nothing. If your answers in step one indicate that this is not a serious issue, I'd probably let it go until the car is next due in for service.
11-21-2004, 08:23 PM
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KLR,
Yeah, I see how leaking oil from the turbo might get into the exhaust. I don't have time tonight to look at the IC pipes, but I did pull the post-intercooler pipe a few weeks ago to retighten it as I was tracking down an idling problem and I noticed there was a light film of oil in that particular pipe. Is it possible to have oil in that pipe?
oil consumption: I added about a litre about 1000 miles ago and it's dropped since then...not good
oil pressure: always close to 5 when driving, goes to down to between 3 and 4 when idling
power: now that you mention, I don't have as much kick in the pants as I used to, but it might be my imagination...
Yeah, I see how leaking oil from the turbo might get into the exhaust. I don't have time tonight to look at the IC pipes, but I did pull the post-intercooler pipe a few weeks ago to retighten it as I was tracking down an idling problem and I noticed there was a light film of oil in that particular pipe. Is it possible to have oil in that pipe?
oil consumption: I added about a litre about 1000 miles ago and it's dropped since then...not good
oil pressure: always close to 5 when driving, goes to down to between 3 and 4 when idling
power: now that you mention, I don't have as much kick in the pants as I used to, but it might be my imagination...
11-22-2004, 02:23 PM
#19
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Sounds like rings to me. . . Plan on replacing the piston rings, head gasket, rod bearings, oil pan gasket, oil, filter, and a few other odds & ends to fix that. Sorry.
11-29-2004, 06:16 PM
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Update
Just got the results from the shop for the compression test
145
145
140
145
Results for the leakdown: very slight leak from intake valves
Therefore: No internal engine leaks
Probable cause for symptoms: leak from turbo, but very small because just a film of oil is present in the IC pipes.
Problem is it has not made any smoke for the last few days and it has never smoked when driving the car.
145
145
140
145
Results for the leakdown: very slight leak from intake valves
Therefore: No internal engine leaks
Probable cause for symptoms: leak from turbo, but very small because just a film of oil is present in the IC pipes.
Problem is it has not made any smoke for the last few days and it has never smoked when driving the car.
12-10-2004, 10:37 PM
#21
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I wouldn't worry about it. If after 1000 miles you haven't burned or leaked enough to force you to add another quart, you're doing fine. Your compression #s are great.
08-09-2010, 11:22 AM
#22
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Jeremy please explain this to me, since I have some oil burning at start up, and my intake is dry so I'm suspecting the valve seals are bad.
Thanks
Thanks
08-09-2010, 11:56 AM
#23
Nordschleife Master
pull the plugs, insert rope to the #1.
rotate twords TDC #1, to compress the rope against the valves, once LIGHT resistance is felt stop and lock the flywheel... remove retainers and springs from valves on #1, replace seals on valve stems, reinstall springs and retainers... DO NOT TRY TO FORCE THE CRANK, YOU CAN AND WILL CAUSE DAMAGE.. make sure the rope is compressable, you do not want to use HARD rope for this...
remove flywheel lock and repeat for #2, 3 and 4 (in reality #1 and #3 could be done at the same time, as could #2 and #4...)
