Hot take: That master tech told me I was wrong about using dielectric grease on spark plugs

I had this older guy at my shop, been turning wrenches since the 80s, tell me that dielectric grease on spark plugs is a waste of time. He said it just attracts dirt and can cause misfires if you use too much. I argued back because every forum I read swore by it for preventing corrosion. After 6 months of doing it his way on customer cars, I had zero comebacks for misfires or rough idle. Meanwhile my buddy who still globs it on had to redo 3 plug jobs last year alone. I started thinking maybe the grease just makes you feel better but doesnt actually help. Has anyone else seen problems crop up after using too much dielectric grease on plugs?

3 comments

3 Comments

charles_chen937d ago

Man, you're kind of mixing up two different things here. Dielectric grease isn't meant to go on the actual electrode or the tip of the plug where the spark happens. It goes on the inside of the boot or the ceramic part to keep moisture out and stop the boot from sticking. If you're globbing it on the threads or the metal tip, yeah that's gonna cause misfires because it's an insulator and blocks the electrical path. The older guy probably meant you don't need it on the threads since they're metal to metal and that's true, a little anti-seize on the threads is way different than dielectric grease. I've seen guys put so much on the boot that it squishes down onto the tip and then you get a weak spark or no spark at all. So it's not that the grease is useless, it's that people use it wrong and then blame the product.

riverhill7d ago

Exactly right @charles_chen93. Seen it happen plenty, guys blame the grease for their own mess.

harperwright7d ago

400 miles and a dead cylinder later @riverhill found out his grease was on the tip.