S40: Grey smoke on start; valve stem seals?

[Asosis]

Originally Posted by difflock54

I am wondering if your smoke could be down to early stage oil seal failure of your turbo. Oil leaking into the turbo gets forced into the exhaust manifold and then expelled.
Would explain the smoke when just started up as the oil buildup is removed.

I'm not an expert on turbos so maybe a member with more knowledge can confirm or offer their views on this theory.
Googling seems to indicate it may be related???

I'm thinking the exact same, as the turbo has done 180.000 miles, is from 1999, and has been peaking at 1.6 bar since 2010/2011.. But I don't see how the turbo can leak oil onto the piston

[difflock54]

The T4 turbo is High Pressure with a larger turbine than say a Low pressure T3 therefore resulting in a greater back pressure on the exhaust side.
Could that excess force some oil back into the cylinders?
I recall once reading somewhere that T4 turbos were normally 0.9 bar?
1.6 bar seems very high.

We need an experts advise here.

[Asosis]

Originally Posted by difflock54

The T4 turbo is High Pressure with a larger turbine than say a Low pressure T3 therefore resulting in a greater back pressure on the exhaust side.
Could that excess force some oil back into the cylinders?
I recall once reading somewhere that T4 turbos were normally 0.9 bar?
1.6 bar seems very high.

We need an experts advise here.

Idk about forcing oil back mate.
Car is BSR stage 3