spark plug change experience

[E55AMG2]

Originally Posted by JCL

I was interested to read the comments on anti-seize being added by various posters. I have never used anti-seize on plugs, and always understood it to be a negative. I never thought about it much, I was just trained to install plugs dry. If they are tight, make sure that you change them when they are cool. If they are torqued properly going in, they come out fine in my experience.

Not sure why there is a concern over aluminum and steel being in contact. Sure, there can be electrolysis and corrosion, but that requires an electrolyte such as water to be between the two metals. It is a concern on the outside of boats, hence the use of zincs, but it isn't a concern for plugs in aluminum heads, IMO.

The manufacturers that started putting a special lube on their new replacement plugs did so to stop installers from using anti-seize and other lubes. It is reportedly nasty stuff, so use gloves when handling those plugs. There are test reports from plug manufacturers that show that anti-seize changes the heat rating of the plug. It is obvious that if it gets on the tip it causes problems, but even a small amount just on the threads was shown to be a problem in some cases.

Just my $0.02. If there are other reasons why anti-seize should be used, I would be interested to hear them.

I think you're 100% correct.

Anti-seize, in my experience, leads to over torquing of plugs. I dont believe they were ever meant to have a lubricant on the threads, and IIRC adding a lubricant to the threads increases the torque value (at least it does on bolts).