Oil Leaking In Rear Middle Cylinder

[Rabbi]

I have oil leaking in the middle rear cylinder, on my 91 Z34. Fouling the plug after about 10 minutes of driving after i replace the plug.

 

When i do replace the plug,i Notice a huge power diffrence, But shortly after the power drops. So Obviously the plug is fouling.

 

When i bought the car i was aware of an oil leak,In the rear. Thats all the guy said.

 

The rear middle spark plug has oil just coating the entire plug.

 

Im guessing its the middle round seal that goes on the bottom of the cam carrior,Am i correct?

 

All i can think of is this seal is bad,And oil is splashing off the cam and down into the plug hole.

 

Is this right?

 

I really havent looked at it,But that is my only guess. I really hope it isnt worse than i think. (although it probobly is.)

 

my car runs fine,But its obviously only running on 5 cylinders.

 

Ive had the car around 4 months and put probobly 3k miles on it.

 

Will running it like this cause further damage?

 

I want to replace it,But im not quite up to par to get into that stuff on the 3.4, Ive done entire engine swaps and headjobs before. But nothing on an engine this big. How hard is the plenum to remove? Does the enginre have to be rocked forward to replace this seal? (if this is even the problem)

[WhiteOut]

I had a similar problem with my car. 5 of 6 spark plugs were completely bathed in oil. Often times this leak is a direct result of leaky valve covers. Its an easy fix and only costs around $30.

[Regal_GS_1989]

Could also be worn valve guides

[sonyman87]

worst case its your head gaskets. but i have heared from a few mechanics that they leak oil with age.

[Rabbi]

will this problem cause other problems if kept untreated ?

[CuttySup]

worst case its your head gaskets. but i have heared from a few mechanics that they leak oil with age.

Worst case?? Try again. It could be leaking from bad piston rings.

[Justin]

Wait, I think people are diagnosing 2 different problems here. Is the top part of the plug covered in oil, as in the spark plug wire side? Or is the bottom electrode side that is inside the motor covered in oil? If the top side is wet, then it's going to be valve cover gaskets. I would definitely get it fixed, you're going to be dumping gas into your oil if it doesn't get burned up by spark. Remember your spark plug wires are probably trashed and oil soaked, so you'll probably need new wires as well.