Oil in the spark plug 4.4 v8

[Mac v70r]

Got back from the dealers and they said it may be oil stem plug seals???? or something like that. But weren't sure. It would be a big job for them. and at £80.00 an hr I wasn't letting them.Especially when they were not even sure!!!

Any body know anything about these? I was surprised to hear that they dont know of any problems with the valve gaskets leaking??.

They reckon my engine might of got very hot at somepoint and hardened the seals. ? They have done a compression test on all cylinders and they are all ok.
They are not sure how the oil is getting into the chamber and getting burnt through the exhaust?

It is going in for the valve gaskets etc on Saturday so will let you know how we get on.

Cheers