I Changed the spark plugs in my OT daily driver(02 Tahoe) because it recently developed a intermittent mis and I figured I'd start with the simple/cheap parts. The number two plug was the first one I pulled out and man was I supprised at what it looked like. Thankfully the rest of them looked normal when I got them out. I don't know how number two was firing at all. Anyone know what caused the buildup on number two and why it was only on one cylinder? Not sure if that could be from oil blow by, moisture, ethanol in our gas, etc????????? Any suggrestions? Thanks
That is usually from an excessive amount oil in the combustion chambe. Does it burn oil? Smoke? I'd say a bad valve seal or could even be a broken ring.
looks like the coolant could be doing that as well. not sure if it would be that insane but could cause a similar problem if gone untreated
Looks like Ash Deposits...from the web the fix is; Verify if you have worn valve guides or valve seals, dont use fuel additives, or you might even try changing fuel brands. By the way, a hotter plug is what most people try to fix this problem. You need to first understand that the plug is NOT typically the problem
I had this on one of my Pontiac engines. There will be no fix out of a can. Like others say, broken ring or valve seal/guide. I bet you are burning oil and its out of that cylinder.
doesn't look like oil, looks more like your engine might have swallowed something, antifreeze, or aluminum filings or chunks?
Looks like coolant to me. I had an O/T suburban with a 350 that had been hot seized by my brothers wife. Pulled into the driveway, it died, steam coming from everywhere. My brother freaked, tried to get it started so he could add some water to get it cooled down and it was hot seized. The next day he was going to push it out of the driveway anf thought he would give it one more shot. It fired right up and ran fine. I ended up buying it from him knowing this and drove it for years doing nothing but tuneups and it ran great. Only thing was, every so often it would pick up a miss, and change out the number 5 plug and it would look just like that but you could actually smell antifreeze on it hahaha. I sold the old 86 burban with 500,000 miles on the clock. (yes it had engines changed etc over the years and miles) I know I put over 100K on that 350 that had been siezed. Scot
So how does it run since you changed the plugs?? If it runs better or normal again I would just leave it for now. Fairly easy and cheap just to change one plug every now and then if you need to. I'm sure guys will bash the Band-Aid approach, but I just did a transmission in the wife's daily. Was really hoping for a Band-Aid instead of a $2500 reman....
I was kinda leaning towards a valve seal myself, just never seen a plug get so bad from oil. So far she runs like a champ again, so I think I will just keep a couple spare plugs and plug wrench in the glove box and see if it mis comes back. It has 180,000 miles on her, so the fact that she drinks an extra quart between oil changes(every 5,000 with full syn. oil) never really supprised me. I bought it from a buddy that had it since new and he said that it always used a little oil. Thanks again!
ive had poor gas do that . it was shell at the time . i would , clean , regap a little more & give it a try . maybe swap cylinders to see if it follows ......... steve
You can always toss an anti-fouler on the plug for that cylinder and see if it helps. I had a 1979 vintage SBC that the PO said it had a dead cylinder. I ran the anti-fouler on it for a while, but wound up keeping a few refurbished (sand blasted...) spark plugs around. Bob
No codes, no light, nothing....... I forgot to add that I don't know how long it's been since the plugs were changed last(my buddy couldn't remember), so it could have been slowly building up over a couple of years. I'm just gonna check that plug ever time I change the oil and see how long it takes to get bad again.
I agree with the oil fouling diagnosis, especially after you mentioned the full synthetic oil. Full syn does tend to leave a little different oil residue than non-syn. Like you said, keep a spare plug and drive it till it drops.
I would suggest you have a slight intake manifold leak into the lifter gallery, pull the intake put in new gaskets oil consumption and plug fowling will go away.
Looks like a junk plug to me. Since you have no idea how long they have been in there....Keep an eye on that cyl for a bit. Looks like the plug started misfiring then just picked up fuel and oil deposits. Run the shit out of it.
X3 4 5 6 7 8.......................................................................... My car did this for 200,000 miles and it was a pain. Every 800 miles or so. Never went through a drop of water.
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