Overtightened spark-plugs...what would you do?

so we've got 20, 12.5 and 15? kind of like, 'how many quarts of oil does my engine hold?' on the plus side, you can be sure if you have it done at the dealer, that they put them in with an impact tool.

 

You have a good mechanic. KEEP him or her!

Some would have tried to scare you into some easy work.

Best of luck with the car.
If you're taking bets....My money says everything will be fine when you yank the plugs at 240 for the next set.

 

Right you are. I'd not found that, thanks.

 

good for you! did he come pick you up and taxi you home?

 

join the club, i don't know how i got home last night. not even sure if i went out.

 

Even though it appears my advice was wrong, I'm glad you reached good resolution to the issue, and I learned something along the way as well.

 

I read something written by a spark plug company that said not to use antiseize compound on the threads because the plugs will be over torqued. Ok then, how do prevent seizing of a steel plug in a aluminum thread? Of course the article posted back in this thread said to use 25 percent less torque; that works too.

 

Here's a guideline, adjusting torque for lubricants:

 

For anyone digging down to the spark plugs, here's a Repair Manual excerpt, showing wiper arms and motor removal, with some torque values. Don't believe it shows the cowl removal as well, but anyway. Again, Nutzaboutbolt's 3rd gen spark plug inspection is invaluable tutorial for this.

 

Seeing how it was a couple of years, since I last reinstalled them, with anti- seize and 20 lb/ft, I checked and reinstalled them again yesterday.

I cleaned the threads and tips with carb cleaner and tooth brush, dry with a rag.

The Repair Manual* specs 15 lb/ft, no mention of lubricating threads. FWIW, my previous Honda Civic (06 hybrid) Shop Manual says 13 lb/ft WITH anti-seize.

DENSO website, says for 12 mm plugs, use 10~15 lb/ft, and dry threads.

Considering the plugs threads felt/looked oily still when I pulled them yesterday, I figure the threads in the cylinder head are still kinda slick, regardless of my cleaning the plug threads.

Accordingly, and after checking wind direction, I reinstalled them with 13 lb/ft. Think it'll do.

* Just to rant a bit about the Toyota manual: the torque spec for spark plugs is way off on it's own, in a blow-up view of the valve cover and fasteners. The rest of the info on spark plugs, ie: recommended plug and gap, is somewhere else in the manual, actually repeated I think, and just about as arbitrary a location, lumped in with something else.

 

I can't believe I am reading this, 7 years later, and that I made the same mistake. I had 13-15 in my notes but then heard him say 20 in the video and was confused. I went inside, did some reading left and right and even googled "torque" in the video comments but must have missed a pinned post with a correction under the video. The video itself really should be edited with an overlay that says "I said 20 but it should be 13-15."

 

Same thing you did 7 years ago?

 

Nooo, 7 years after this was posted, and I made the same mistake as the poster, so people (like myself) are still making mistakes because of an error in the video, despite a pinned post with correction. Yeah, my phrasing was a bit off, good catch.

 

For a G3, overtightening spark plugs isn't much of a thing unless you REALLY over-tighten then and get to discover what helicoils or serts are. If you over-tighten them without damaging the head then it might be a problem........at the 250,000 mile point.

 

Denso's spark plug literature says the plating they put on their plug threads is what does that job for you, and they discourage adding any lube.