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-   -   oil smoke at startup - again (https://rennlist.com/forums/996-turbo-forum/197896-oil-smoke-at-startup-again.html)

mwilson 04-15-2005 09:29 PM

oil smoke at startup - again
 
Kevin suggested checking the turbo sumps; I finally did that. There was a small amount of oil each side - well less than a US cup measure. I believe that means the drain-back valve is OK. Also both turbo compressor sides looked fine.

Any other ideas on what the smoke could be? I want to clean this up, because it creates an awful smell with the climate control on in the first few minutes of operation, and this IS supposed to be a luxury GT car, so the climate control should not be polluting the cabin.

Thanks,
Michael Wilson

t urbo 04-16-2005 06:10 AM

michael,
has the smoke got a blueish tint to it? Does it happen occasionally or all the time.
If it is blue smoke every so often on start up then this is perfectly normal. Everyones does it from time to time but most people dont notice. Its due to the boxer engine design and is where a very small amount of oil passes past the piston rings whilst the engine is off and cooling down.
It happens more if you have started the car then switched it off without it heating up (piston rings havent expanded properly so will allow the oil past when stopped),then next time you start it you get the blue smoke.

1AS 04-16-2005 10:19 AM

mwilson's sounds much worse than the brief puff we all get from time to time. I see the puff in the mirrors, but have never had it sucked into the climate control. No helpful sugestions, however. AS

WCE 04-18-2005 09:51 PM

My '02 manages a dramatic smokey startup about 3 times a year (that I've noticed). No common denominator between the events would explain them.

Ironically, the first time it smoked was right after showing my $100k car to my very skeptical parents - they weren't impressed. Just last week, my wife was actually admiring my spring detailing job, as it filled the driveway with smoke when I pulled it into the garage! Also not impressed!

Kevin 04-18-2005 10:18 PM

http://forums.rennlist.com/upload/p1010064_copy2.jpg
This is a picture of a recent failure of a K24 turbocharger that was run for less than a year.. If you can see the gap in the sealing ring inside the bearing housing.. This seal measures .0065 where .007" is high limit and worn! This customer did not practice good shutdowns.. Oil will weep out of this gap and fill the turbine housing up with oil.. On start up you car will burn the oil casuing the smoke show.. One misconception is that poeple will say that the smoke will stop.. Well the truth is, once the cats reach operating temp, the cats will eat any smoke.
http://forums.rennlist.com/upload/p1010102.jpg
This pictures shows 4 turbine wheels from 4 sets of leaky/failed turbochargers that I seen last week. 2 shafts are from fellow Rennlister's.. The bottom shaft is from a low mileage '03 996TT that had smoke show issues. The customer was upgrading to Stage 2 turbochargers, but wanted the situation fixed.. If one looks closely all the shafts, they are all blue with various stages of heat damage.. The heat accelerateds the wear on the sealing ring. As it wears the width and side clearances grow.. If you can't take some time to cool your turbochargers down, this is what you are going to face..


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