Smoking problem: Fixed

[4.8iS Le Mans_NZ]

Originally Posted by X5only

Both pipes, pcv and pcv surfaces were generally clean ... I got a sinking feeling in the pit of me wallet

I chatted with my indy and asked him how come there's no smoke at startup if the valve stem seals are leaking. He says when the engine is off there's no vacuum, the leak occurs only under high vacuum conditions. Is this explanation plausible?

Would be plausible only if the idle vacuum is greater than the vacuum present at higher rpm, which seems wrong to me.
Have you considered trying the thicker oil solution?