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      09-21-2015, 12:24 PM   #10
493263
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Drives: 2011 550i xDrive
Join Date: Aug 2014
Location: DC

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Quote:
Originally Posted by HR F10 View Post
Got my car back today and was told the blue smoke is most likely from me having catless down pipes.
I know catless downpipes will cause some smoke but I thought it was too much lately. Maybe I'm being paranoid, I'm going to leave it alone for now and if it gets worse I will have the turbos inspected by an Indy shop.
Blue smoke is caused by burning of oil in your combustion chamber. It commonly comes from leakage of oil into the cylinders. Check your piston rings or turbo seals as it is the most likely scenario. My 550 had blue smoke and they tried to say it's normal. I had to ask them 2 times and waste them a lot of time/money until they finally decide it's the turbos and all tubings/seals had to be replaced. Now I no longer have blue smoke. Just FYI.

Need to learn about these things instead of relying on the mechanics to be truthful.

White smoke = most likely water vapor
Blue smoke = oil burning in cylinder or exhaust(from turbo)
Black smoke = bad fuel mixture due to incomplete combustion because of suboptimal air/fuel mixture.
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