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Smoke issue

Tiny
NASER NASER
  • MEMBER
  • 2011 BMW X5
  • V8
  • TURBO
  • 4WD
  • AUTOMATIC
  • 114,000 MILES
Am very familiar with BMW's and sold tons if them, usually on inline 6 motors it is pretty easy because there are no turbos and PCV issues are infamous. So I replace them and it goes away. But with these v8 twin turbos which are infamous for smoking it is more difficult as it could be the valve stems.
So basically the car starts runs and drives great with lots if power and no codes.
If you leave it idling for say 10 minutes and then hit the gas you get a puff of smoke. Then it goes away.
How do I know whether this is a PCV, valve stems, or even rings or head gasket. No overheating.
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Wednesday, July 15th, 2020 AT 4:07 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
Naser,

There is no easy answer to that other than checking things. Have you pulled a valve cover to see if the returns are partially plugged? Does it do it when you first start the vehicle? Is there any blue smoke at WOT?

Joe
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Wednesday, July 15th, 2020 AT 6:19 PM
Tiny
NASER NASER
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  • 836 POSTS
No issues when I first start the car, only after idle then it goes away after taking off. Mainly does it in this hot weather. Bluish smoke when I hit the gas pedal. If I leave it running for a while it will eventually start to smoke lightly, but only notice once you hit the throttle. Didn't remove valve cover. Can you explain why would returns if plugged can cause such a thing?
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Wednesday, July 15th, 2020 AT 6:29 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
If the returns are plugged, it could simply be filling up in with oil under the valve cover. At a lower RPM, it can be more noticeable.

I would pull the covers and inspect the valve seals and make sure the engine is clean inside. I have to be honest, Naser, mounting the turbochargers and exhaust manifold within the valley creates excess heat near the cylinder heads, which prematurely hardens and causes excesses wear on the valve seals. That is what I think is happening here. There was actually a TSB that was put out regarding the issue.

Let me know if you need anything.
Joe
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Wednesday, July 15th, 2020 AT 7:20 PM

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