My car has been sitting since October and decided to work on my car a little for some upcoming changes to my set up. I was changing my plugs and found some oil on the threads in the cylinder closest to the firewall.

I did a compression test and that cylinder was lowest with a compression of 202 with the rest around 215. I have an EMS so I think my readings are a little lower because the EMS draining a lot of the battery(battery was dead after the test).

My question is if this has happened to anyone else? I am pretty sure its the little valve cover rubber seals. At the worst it could be the valve seals but don't know if this has happened to others.

I know for a fact its not the piston rings as there is no oil on the tip of the spark plug. The oil on the plugs was found between the plug and the washer on the plug.

Lastly, I have over tightened that plug once before.


I am going to hook my battery to a charger and try a compression test again.

Chris E.

 

Oil on the plug threads is not unusual. Next time, after a few thousand miles of driving, pull the plug and look down the hole. You might likely see a bit of oil pooling at the bottom of the hole just before the threads. It's not coming through the plug threads from the cylinder. I wouldn't worry about it.

 

Thanks for the input xviper
I was not too worried, but thought it was a little more oil than the rest of the plugs.

Thanks

 

i had this problem way back when I had my hatch with b16 motor... after taking of valve cover (while replacing cams) i put the cover back on but it wasnt tightened down all the way.... so there was room between the head/gasket/valve cover for the oil to leak down into the spark plug holes...


Jay

 

Question is--how does oil on the threads effect torque wrench readings.....?

 

 

It doesn't seem to affect the torque at all. Whenever I take out my plugs, I always check to see what torque they are at before I unscrew them. After the spark plug recall when the new stainless steal crush rings were introduced, there was no change in torque after the plugs had been in there for a while. Of course, I use anti-seize compound when I install plugs and this isn't much difference from when mechanics squirt oil on threads of some bolts before installing. It's far worse to install such things with dry threads.