Replaced Plugs, check out the oil and odd plug number...

[Robbabob]

I just replaced the plugs after the purchase a couple weeks ago, now 106+K miles. Check out the oil on the threads, not on the electrode, though.

Also, check out the 985 for cyl #4, 981 for the other 5. Put in 41-103's.

View attachment 25939

 

[shrek77]

That means that the check engine light was on right before you bought it and they went the cheap route to remedy the issue.

 

[CaptainXL]

Check out the oil on the threads, not on the electrode, though.

Due to a combination of blowby pressure from the crankcase and worn gaskets. There are 6 individual valve cover gaskets for the spark plug wells. Oil is blown into the wells past the gasket and ends up into the threads because the oil is so thin. Keep an eye on it. At some point I plan on replacing the valve cover gasket set. But if you have a lot of piston ring blowby there probably isn't a whole lot you can do about it to totally seal it up.

 

[Ed H]

Welcome to my world. I bought a use 2002 TB in October with 156k on the clock. When I changed the plugs they all looked good except #3 that had massive amounts of oil on the threads and electrode. It appears to be a leaky valve cover gasket - and I pray that is all it is. I could see signs of oil seepage from the seal, down into the plug socket. I think they tried to clean off the walls of the plug area, but not good enough.

All 6 plugs were the same type though.

At 106k, your truck is still a baby. Take good care of her and she'll last a very long time. As I am sure you have read, change ALL fluids immediately unless you have maintenance records. Mine did not.

 

[gmcman]

Also, check out the 985 for cyl #4, View attachment 11834

Seems like that plug is for a V8 , overall length is way off also. Sure will prob run smoother with the fresh set.

 

[97blazer]

This thread is a bit old but I finally got around to digging up some links to help with "reading" of the plugs. Also with all due respect to everyone (caution rant) I can't believe that oil is getting past the plug and onto the threads. First there is no "gasket" just a tapered seat. Properly installed, nothing is gonna get past that seat in either direction. If the seat was bad you have one heck of a compression leak. Anyhow just my opinion.

Anyway, here's the links that among others will help with determining various issues your engine may have.

The first is the classic plug reading chart, the others are more technical.

FAQ Reading Spark Plugs

sparkplugreading

How to read Racing Spark Plugs

 

[NJTB]

Seems like that plug is for a V8 , overall length is way off also. Sure will prob run smoother with the fresh set.

At least whoever did it used a shorter length plug. I worked on a car once that the owner put a longer reach plug in and burned a hole in the piston.

 

[Robbabob]

YIKES! Can't believe anyone would put anything other than spec, or at least "educated" alternative. Get in a bind and use 1 different until soonest it can be replaced.

TLC is all they need to last a LONG time.

 

[Ed H]

Here is the plug I spoke of above. Note the puddle of oil and obvious leak in the next photo.

The others looked perfect.

I hope I don't have oil coming from the top and bottom... The bottom would not be good.

View attachment 26084

View attachment 26085

 

[Sparky]

Oil gets on the threads because it is on top, and as you unscrew it the oil runs down the side of the plug onto the threads. Nothing to worry about there. If you were getting that much fresh oil on the bottom part of the plugs it would be burned while the truck is running and leave black residue, not still liquid oil.

Also I've yet to see an inline engine with deep plug wells like these from any manufacturer not leak some oil onto the plugs later on. I'd only be concerned if it was a lot. That isn't a lot.

 

[Ed H]

Thank you Sparky. I will sleep better tonight. Honestly. I have been almost afraid to post those pics...

 

[mrphoenix80]

And certinly not enough to justify the hassel of pulling the intake back to replace the valve cover gaskets.

 

[Wooluf1952]

Agreed X2. If the rings were bad or any problems, the bottom of the plug would be loaded with oil.
That plug looks like you're getting a good clean burn.

There have been members that were getting CEL's for misfires, when the well filled with oil.

 

[mrphoenix80]

There is also a TSB for misfires on cyl 4 because water can bypass the hood seal and the coil seal and fill the well. I have seen that a few times also.

 

[Sparky]

Ha, like mine. My plug has been submerged at least twice and the end of the coil rusted, but I cleaned the electrode with sandpaper and it still works fine Probably should replace it sometime but until I stop the water from leaking into there in the first place I'm not going to put a new coil in to end up with the same problem.

 

[Robbabob]

Glad this thread has kept going with the latest comments. The initial ones did have me concerned about a ticking time bomb; as long as no CEL.... Inside the tube looked pretty much like yours, more of a long-term weep.

I wonder if high-mileage oil will help cure that..... or, have I been reading the marketing (lies) of oil too closely?

Good on y'all!

 

[mrphoenix80]

Probably should replace it sometime but until I stop the water from leaking into there in the first place I'm not going to put a new coil in to end up with the same problem.

You could try
Install AIP seal, P/N 25788476. The revised seal has a foam weatherstrip attached to the bottom. The foam weatherstrip faces the air inlet grille panel.
Or
Something like it