940 white smoke

  #1  
Old 01-13-2019, 03:39 PM
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Default 940 white smoke

my exhaust randomly putting out white smoke. It is cold out side but I thought that was supposed to stop after warming up. It seems to only happen while idling.
 
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Old 01-13-2019, 05:07 PM
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a little white steam is normal in cold weather, gasoline is a hydrocarbon, and when you burn hydrogen and carbon with oxygen, you get CO2 and H2O ...

massive big clouds of pure white can indicate a head gasket failure, but when that happens you'll usuallly have smoke bubbling out of the coolant overfflow bottle, along with oil slick rainbows...

clouds of light BLUE smoke generally indicate burning oil.
 
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Old 01-13-2019, 06:13 PM
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Thank you for the reply. I finally located a source of leaking of oil coming from the bottom of my turbo it seems. There is a nut missing where there is supposed to be 2 thereís only one still and pretty good dose of oil is around the turbo. Hopefully this just means itís not got a good deal around the turbo and not something more sinister.
 
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Old 01-13-2019, 07:30 PM
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oh yeah, turbos are another source of oil and/or water in the exhaust... they have both oil and water plumbed through them for lubrication and cooling. the turbine inside spins at an insanely high speed, like 100,000 RPM or something, so the seals on the bearing shaft is pretty fragile. they can also spray oil into the engine intake, whereupon the engine turns a very small amount of oil into lotsa smoke.
 
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Old 01-13-2019, 07:33 PM
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Originally Posted by pierce View Post
oh yeah, turbos are another source of oil and/or water in the exhaust... they have both oil and water plumbed through them for lubrication and cooling. the turbine inside spins at an insanely high speed, like 100,000 RPM or something, so the seals on the bearing shaft is pretty fragile. they can also spray oil into the engine intake, whereupon the engine turns a very small amount of oil into lotsa smoke.
thats good to know. Turns out itís the oil return line thatís connected to my turbo that has a missing nut. Iím also pretty sure I have a clogged PCV. Do you think that could cause my turbo to leak oil?
 
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Old 01-13-2019, 08:36 PM
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you mean the nut on the banjo fitting? if those were missing, the oil would be pouring out the opening. and no oil pressure in turbo, it self destructs the first time you wind it up.
 
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Old 01-13-2019, 09:26 PM
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Default Not sure

Not sure what you mean by banjo fitting but itís the line the comes from the oil pan to the turbo and itís the two nuts on the turbo itself. Only one is missing and itís a pretty descent leak but not enough to show much of a spot on the ground. Itís very light leak.
 
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Old 01-13-2019, 10:10 PM
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oh, that one is the oil drain, low pressure oil out of the turbo back into the engine oil pan. my 740T had a drip for awhile which was tracked down to a missing seal where that downpipe sticks into the block. There's a banjo fitting on the pressurized oil input line (and I think on thee two coolant lines). here, this is a fancy braided oil line, with a banjo fitting on top... I believe the stock oil line is a thinner pipe, but it too has a banjo...







 
  #9  
Old 01-14-2019, 08:25 AM
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Originally Posted by pierce View Post
oh, that one is the oil drain, low pressure oil out of the turbo back into the engine oil pan. my 740T had a drip for awhile which was tracked down to a missing seal where that downpipe sticks into the block. There's a banjo fitting on the pressurized oil input line (and I think on thee two coolant lines). here, this is a fancy braided oil line, with a banjo fitting on top... I believe the stock oil line is a thinner pipe, but it too has a banjo...


alright sweet. So if itís just the oil return seal leaking due to a missing nut I should be okay until I can get it to the shop right? I know it could probably get ugly if that other nut backs out.
 
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