Oil? in the coolant

If it's oils, it's not the Bars.

Your fears are very well founded.

No.

No, oil. You know it's oil ;-)

Do you mean regrind the valves? It depends on many things - the mileage of the car, the results of a pressure test on the head, and how long you intend to keep it.

In general, when I have a head off, I won't regrind the valves unless there's a good reason to do it. I will, however, change the valve stem seals and have the head skimmed.

Some years ago I had a new headgasket (for my 93 9k, not myself:). The symptoms were poor running and hesitation. However I don't think there was oil/water mix in this case but the error code indicated the headgasket.

Naturally, oil/water mix is a fairly sure sign of a blown headgasket, but could there be a mild case without oil/water mix? Anyway, the garage replaced headgasket, but said head that head skimming was not needed in my case. Does it make sense? The car has been fine since, in fact remarkably well behaved. Johannes

You can certainly have a failed head gasket without water/oil mixing. For instance, you can have combustion gasses leaking into the cooling system.

In theory, what you do is check the head for flatness, and skim only if it's at all out of flat. In practice, when I have the head stripped down I take it to a small workshop where they pressure test it and skim it as routine. This guarantees that I'll get a good seal with the new gasket.

But will skimming change the compression ratio? Could that have an ill effect on a turbo?

Minimum cylinder head height and machining limits should be in Bentley, Haynes, and possibly thru other sources