Hey , Guys,

These plugs has been in the car for around 6500 km on a rebuilt stock engine, stock tune.

They look OK, what do you guys think?

BTW what that yellow stuff on plug #3?

Cylinder
#1


#2


#3


#4

 

looks like you are getting corrosion on them spark plugs lol. I would replace them and just get ngk coppers. Not denso's. There about 3 bucks a piece. I usually replace mine every other oil change. Depending on how I have been driving

 

Cheers for the input, corrosions can be caused by?

I hope it's not engine problem!

Come on guys let see your plugs~!

 

Since it's only on the top i would think that the spark plug coil isn't sealing properly to the head causing water to get down into there, it's not that big of a deal.

Had these ones in the car for a while
Cyl 1-4 left to right

 

The yellow stuff on the ceramic above the hex is the glue they use to attach the two parts of the plug. It shouldn't burn and run like that, I usually only see that on lower quality plugs; Autolite, Champion, Motorcraft, etc. Almost never on NGKs, part of the reason I won't run anything but no matter what the vehicle is.

Anyway, they all look pretty good, #1 is running a bit cooler than the others for some reason, but we really can't see the ceramic and tip on 2 and 3 which is going to be necessary for a good read.

Also, is that fluid on the threads? If so, what kind? They should be coming out dry.

 

I think the threads has some oil on them, is that bad?

 

your looks nice and unanimous, 8s good for a stock engine?

 

I have always ran ngk one step colder on my stock engine without 0 problems. I love them lol. I use to use iridium plugs and always had problems. It wont hurt anything to run them.

 

There really shouldn't be any way for oil to get on the threads to begin with...

Which means it's either coming down from the valve cover and running down the threads when you pull the plug out or getting on there from inside the combustion chamber.