Reminded by the 'no anti-seize' comments about plugs. When , with my first pickup, watching a mechanic with power tools struggle to change lug nuts I changed my mind . The comment was "never use anti-seize on the lug nuts." Well I'm in the 'rust belt' so I've always used anti-seize on those lugs and know many others that do the same. So what's the difference with plugs .Obviouly they don't see salt and water .But with Al heads ? Do I remember that the VW bug used graphite ?
With aluminum heads especially you have different types metals in contact with each other and current running between them. This increases the chances of corrosion between them. Plus combustion gases try to work their way into the threads and build up carbon deposits.
Most plug manufactures account for bi-metal corrosion. They apply coating to the thread area to prevent seizing. I could post pages about the problems of improper use of antiseiz. ,,,, even on lug nuts !
I can only speak for my former 5.4 but iirc, Ford issued a TSB suggesting the use of anti seize compounds on the problematic head/plug design of the 5.4s manufactured before, I think, November or so of 07.
