Problems with head gaskets
It is not always easy to find the head gasket for a car of which few have been made.
If there is no replacement to be found, there is nothing left but to make a new gasket.
Tags PTFE
An addition that works: TSL
TSL is a petroleum derivative that significantly improves the lubricating action of engine and transmission oils. It is free from PTFE or Teflon. The addition to the oil is approximately 5% and that reduces friction and wear
Castor oil or super juices: oil additives
Oil additives promise a lot. But make little sense.