Hi Alwyn,
To correct any misunderstanding , I too, use copper slip on the threads, and totally agree over tightening and cross threading are an issue.
My problem was tracking. Water moisture remained somewhere between base and tip of plug/boot. So the outside of the plug is coated in dielectric grease.
The cover plate is belt and bracers and I know subjective. But, should I wash but not use my car at least I know water is not sitting in the plug well until next use. And your right......I should use it more!
Kindest regards
Salmo
