E90 320 n46 smokes

[wonderB]

Hi all..i'm a mechanic but I'm just a bit disappointed by how quick 1 e90 got smoking at tail pipe ao soon. The BMW has 140k on the clock. I dismantled the whole engine and now am busy installing new piston rings and valve seals..i can see oil was moving past the rings into the chamber hence getting burnt. I found that the oil ring expander was facing down..so how can a bmw specialist do this..anyone with same experience?

 

[Chucky]

Hi Wonder B, The valve stem seals on these motors are usually the culprit when mileage is above 100 000ks. Check this forum and the internet the n42/n46 motors are notorious for smoking due to the valve stem seals failing and after replacing them the smoking is gone.

Hope you do get your problem sorted but taking the engine apart is/was extra work.