Hello,

so I checked my plugs as I try to do as much as possible (ok about yearly) and no 4 was loose again and coil pack is all gunked with burnt oil. I’m guessing the threads must be bad in the head. This is not the first time this cylinder’s plug has come loose. What can I do? I thought of using some high temp blue LocTite but it seems that the consensus on the Internet is that my engine will explode if I do that.

I snapped a pic of my coils. They are in the order of the engine. No 1 looks like it was never used and no 2 & 3 are dark blue and 4 is gunked from the loose plug. What gives? I guess it’s the excess heat coming from 4 that darkened 2 and 3 ?

 

You can use "very small" drop of Red loctite This red stuff melts at 500F.

 

They all leaking a bit but #4 is the most.
Have you been using anti seize while installing these plugs?
What brand of plugs?
Did the old plug came out with some effort?
Every Fit I see now on the junk yard has leaking plugs BUT they are TIGHT!
I would suspect a crack between the threaded hole and exhaust port