A damaged spark plug thread that leaks under combustion can be noisey
in a way that I suppose could be described as VW-like.
I don't like to dampen your spirits, but I'd be seriously interested
to know how oil pressure could affect the spark plug thread. It may be
that the guy you talked too had his mind on other things.
What I'm guessing is - the 'melted thread' effect is caused by the
thread being stripped out of the head, which has been cause by a
careless mechanic overtightening the plug. Although to get to the
stage where the plug just pops out means this has been done very
carelessly indeed.
It can probably be repaired with an insert of some sort (eg Helicoil),
but this will almost certainly require the head to be removed. I
expect you will find out when you try to put a new plug in the hole -
you won't be able to get it to tighten.
Try to avoid driving the car with a missing spark plug. You will not
only make a mess of things under the bonnet, but you may damage the
crankshaft, which will have an unrestrained load on one cylinder.
--
Stewart Hargrave
For email, replace 'SpamOnlyToHere' with my name
