Originally Posted By: Number_35
[Trav, I do this as well - there are too many horror stories of seized plugs. I use NGKs, and have never understood why they say not to use anti-seize. I had to leave several plugs on a friend's Windstar after they didn't want to budge - I was afraid of stripping the threads. A dab at the factory would have been great.
In fact, I use it on pretty much everything (but no, not head bolts, although it's been a long time since I had to deal with them). Do you de-rate the torque for critical applications?
Yes depending on the anti seize you need to reduce the torque if the manufacturer doesn't spec torque value with lubed threads. Generally I reduce it by 25% but many plugs today are very difficult to even get a torque wrench near them never mind use it.
I tighten them firmly not nut busting tight and never had a problem.
The worst engine I ever saw was the Ford Kent engines, when you bought them new bring it home, remove the plugs and never seize them or you may well be pulling the head when you need to change them, used always make sure the plugs come out before buying.
Originally Posted By: Yup
I've heard rumors NGKs have some type of coating on their threads that act as anti-seize. Don't know if true or not. And they don't want double anti-seize. I always add a dab or two...doesn't take much...and haven't had issues.
It helps but doesn't prevent this all the time, all it takes is once to make someone a believer in the value of anti seize.
The reasons they don't recommend it is the average DIY may not reduce the torque and strip the fragile aluminum threads or use to much and cause a cat damaging misfire. It opens up a big can of worms they rather not deal with.
On the other hand manufacturers have no problem specing it for problem engines like the Ford 3V V8 and Champion actually makes a ceramic based spark plug anti seize.
Originally Posted By: sxg6
Kinda funny, briansmobile1 just released a video related to this subject. Some of the stuff like using anti-seize and dielectric grease might be obvious, but I like the tip on using a dremel on an old spark plug to clean threads.
You can make a home made thread chase with a dremel tool on any bolt but for plugs its easier to spend $8, the nice part of this little tool is the other end is 18mm and the correct thread for O2 sensor bungs (its real use was for 18mm Ford spark plugs).
https://www.amazon.com/Lisle-20200-Threa...g+thread+chaser