Oil on spark plug question

RoadracerGT · Mar 11, 2006

Car is a 99 V6/auto convertable and is my girlfriends car. Car has 102,000 miles on it and as I was doing a spark plug change, I pulled the drivers/3rd back plug(the one at the firewall). I noticed it was covered in some oil and the ceramic part was kinda worn down.

All the other plugs looked decent. The car has always ran fine, if not great. Got plenty of power, no oil issues or smoke and sounds good(no funny noises i'm aware of). I think it does have a pass. side exhaust leak, which seems to be verified by the searches i've done on here, as a common problem.

More concerned about that plug/cylinder, though. I'm thinking if the car is doing everything great, that it could possibly just be like a valve stem seal or something. When I changed the plugs it had sat for about 4 hours so I figured that gave it some time "drip".

Can any of you guys help me, or confirm what I think is possibly the problem. I know alota you guys "mod" these cars, but this one is just bone stock so it's had no "harsh life" to my knowledge.

Thanks for any and all help, i'm just not too car savy as i'm still trying to learn things on my 4.6.

Lsredy2kstang · Mar 11, 2006

You know my back two when I changed them were bad looking. It could be something to worry about with 100k on the odo. I have never had an issue. I think that it may be normal. When we did it we did do a compression test as well and all the cylinders were within specs.

So I would check that and see if anything was out of wack.

Then drive it till it dies.

Skymarshal · Mar 11, 2006

Was the oil on the ceramic insulator that's inside the combustion chamber, or was it on the body? An oil covered plug usually means ring blowby, but you'll notice a lot of blue smoke, even with just one cylinder leaking.

If there was oil on the upper body, you could have oil pooling in the spark plug well. That's usually caused by a leaking rocker cover gasket. Normally, the leak is slow and it's really no cause for concern. If the oil in the well gets really deep, it can dissolve your spark plug boot, and the boot will come apart next time you pull it off the plug. That's no big deal if you run platinum plugs! By the time it's time to replace the plugs, the wires will be ready for replacement too.

TMX · Mar 11, 2006

Also, the 99-00 V6 had problems with oil coming through the PCV system. I had oil on my plugs, most of it was on the back 2, more on the passenger side closest to the firewall than any others. Installing a seperator or an inline filter helps with this alot. http://www.miracerros.com/mustang/pcv_filter.htm here's a site that explains the problem, and gives a cheap, effective way to fix it.

RoadracerGT · Mar 11, 2006

Thanks for the insight everyone. The spark plug in question had oil on the ceramic part of the plug, and you could see it was causing a deffinite "issue" with the plug.

However, I just can't imagine how there was no codes being thrown, no smoke.......of ANY kind out of the tail pipe, and the engine sounds solid to me(minus that pesky pass. side header leak).

I replaced the plugs with a some cheap copper ones, before ruining another set of higher dollar platinums. I'll pull the plug back out and check for a re-occurance of oil issue.

Thanks for help and ideas guys.

Oil on spark plug question

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Oil on spark plug question

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