Thanks, well as I mentioned the threads are all good, just a touch loose. All those other applications you mentioned are all normal engine temp areas; these studs are a lot higher temp being where they are. If the truth be known, the rated temp of 204C is a conservative one which companies do to protect themselves in the 'safe margin' and could possible go a little higher. But in a situation like mine where there is a little more space to fill between the threads, how will it seal after 15 years and thousands of heat cycles? But I will just go ahead and use the Permatex the way NH9 suggested and will sleep well.
