Manfred

Started having an issue under acceleration today--car gets up to about 4000rpm in 3rd gear and then acts like it's missing. Goes from 4k-6k rpm in 1st and 2nd without a hesitation. I was suspecting an ignition problem and was planning on doing the firefly test tonight. In the meantime I thought I'd check one of spark plugs 'cause it's always sat up a little higher than the rest (on seven of the caps they sit about 1mm below the edge of the engine, on this one it sits about 1mm higher than the edge).

I pulled the plug and found oil around the edge of the plug and a small amount in the hole. I just changed the plugs about 3000 miles ago and this wasn't there.

My oil consumption has been about 1 quart every 500miles and hasn't changed at all in the 10k miles I've had the car.

Could the oil in the cylinder be related to my recent loss of power or should I still be thinking electrical first?

Arrows are pointing to oil around seal.



You can see oil around the bottom lip.

dprantl

Oil around the spark plug usually means the seal around the hole on the valve cover is starting to let go. Valve cover gasket replacement is the cure for this. I doubt this would be the cause of your hesitation, unless the plug you are talking about was never fully seated.

Your running issue is probably plug wires, coils or the amps for the ignition system by the hood latch.

Dan
'91 928GT S/C 475hp/460lb.ft

JHowell37

The amount of oil there is not significant.

ammonman

Do you know if the plugs were properly torqued the last time they were changed? During my recent Cam Cover R&R I pulled all the plugs to inspect them as the car is still new-to-me. There was hard oil residue on the threads and the crush washers had never been seated. I suspect the last person to change the plugs did not use a torque wrench to tighten them. When I used a torque wrench to re-install and tighten, it felt like there was some burned on oil residue in the spark plug hole threads that was being pushed (crushed?) out when I seated the plugs. All eight of the wire caps were about 1mm below the surface of the Cam Cover when done.

Just my $0.02
YMMV
Yadda, Yadda, Yadda

Mike

Manfred

Thanks everyone. I was hoping the consensus would be that that's not a lot of oil.

Sure do, I did it myself. And no, I didn't use a torque wrench. That is the crush washer that the oil is on in my picture--I'm not sure what it's supposed to look like but I'm thinking I never seated it fully. On reinsertion this time the cap is now about 1/2mm below the surface of the cam cover--not quite as much as the other seven but definitely in more than it used to be.

When time and money allow an intake R&R is on the list of things to do. The valve cover gaskets get changed in the process, right? If so, something like this can wait a little while right?

Well, the hesitation is new as of today and the plug has been that way for at least 3000 miles. I was hoping I could get it to seat better and eliminate that as one possibility and that's when I found the oil.

That was my first thought. I have suspected before that I might have a shady coil 'cause I've gone to four cylinders twice before but this is obviously manifesting itself differently.

not familiar with these

Thanks again (I feel much better now),
Dan

dprantl

Yes, that leak is extremely small. The valve cover gasket job includes the two gaskets, the plug hole seals, the rubber bolt spacers and washers. When you have oil pooled in there that covers half the spark plug, then you should start to worry (BTDT).

Dan
'91 928GT S/C 475hp/460lb.ft

Manfred

Good deal.

Manfred

Good deal.