[LaCross]

It is possible that im crazy.

On my way home from work today, I was sitting in traffic, and noticed quite a bit of blue smoke coming from my car. When I stopped it would come into the cabin. (window was open)

traffic let up a little bit and it seems to have stopped? Im not understanding this. Does this happen? Can anybody explain?



2010 135i 6mt 80k miles fbo

[LaCross]

Now the thing isnt smoking... Anybody know what can cause oil burning only temporarily in traffic?

[N111CUK]

water pump can cause smoking

[LaCross]

Originally Posted by N111CUK

water pump can cause smoking

it was oil smoke

[JamesM3M5]

I put together an engine recently which also smoked like crazy for a short time and quit. Additionally at the SAME TIME the vacuum pump suction went out. Got it back to the shop and replaced the vacuum pump with another good, used one. The pump was full of engine oil that shot out of the oil port when I turned it by hand. Once I cleared out the excess oil, vacuum was fine again.

So why did the engine smoke on occasion? It cleared up on its own.

My thought: sudden loss of control on the pressure regulator side of the oil pump. In their crazy quest for effficiency, BMW installed a sliding vane variable flow and pressure oil pump. The later N55 and other cars have a MAP controlled system, while the N54 and others have a simpler mechanical feedback.

Only thing I can figure is that they can suddenly push way too much oil pressure/flow and then work normally again. The sudden shot of oil can push into the vacuum pump, oil squirters under the pistons, etc, and possibly cause a temporary oil smoke issue. Or maybe it could be oil burped into the intake from the PCV.