Thread: Tappet adjustment now black smoke.

I assume it's a Tdi ?

The missing valve stem cap will only cost around $2 to replace and it's needed to ensure the rocker/value contact point is uniformly loaded throughout it's travel and does not put additonal lateral loads on the value and value guide, probably the rocker shaft too. I'd replace that first, then re check the tappets and see if it's still smoking.

Replace all the valve stem caps, if one has gone, the others won't be far behind.
You don't have to lift the rocker gear (although it does make it easier) just wind the adjusters all the way back and you can slip the caps out and replace them.
It just saves undoing the bolts in the head which may strip and have to be angle tensioned (IIRC it's around 5Nm then 50*)

As to the smoking, sounds like an air blockage somewhere. Check the usual suspects, air cleaner, turbo hoses for internal de-lamination, etc.