View Full Version : Oil on Plugs

08-24-2006, 09:41 PM
A buddy of mine has a SR20, with some mods. It didnt seem to be making the power it was supposed to and the car would smoke, not alot thou. We decided to give the car a once over. We decided to check compression first. When we pulled the spark plugs 3 were ok, but one was full of oil. We did a compression test and it was 150 across the board. We are thinking its bad valve stem seals, or worn valve guides. What do you guys think?

08-24-2006, 09:47 PM
You could have also gotten that oil on your plug when you pulled it out of the hole, if your valve cover seal is bad on that cylinder. Does it only smoke at certain times? like whenever you start it up for the first time a day? or just constantly?

08-24-2006, 10:11 PM
Yeah I thought about bad valve cover seals, but the coil and top of the plug were clean, and there was oil in the bottom of the plug. Hopefully my buddy chimes in, but it doesnt really smoke at start up, but after its warm it will consistantly smoke, we were on the highway the other day just crusing and a decent amount of smoke was coming out.

08-29-2006, 11:50 PM
I am having the same problem. Has this happened to anyone? When I pulled the coil out to inspect the spark plug the cylinder was dry with not a spec of oil, but once I pulled out the no 1 plug it was soaked in oil. I performed a compression test and it was 155 across the board. Is this oil coming from a bad valve seal? Anybody?

08-30-2006, 01:06 AM
If compression is good and there is no oil in the plug wells, the most likely place is the valve seals. It could be due to bad seals or worn and out of tolerance valve guides.

08-30-2006, 01:46 PM
A leakdown test will help you isolate the problem.

08-30-2006, 02:10 PM
Just to chime in...

I have the exact same problem. I found oil on the bottom of spark plug #2 and my car smokes once warmed up. It will also blow a decent size "puff" between redline shifts and higher (19psi) boost levels. I was thinking that it was the valve seals cause... well it was just what I thought.

08-30-2006, 05:27 PM
I just had this happen to me. Was taking my head apart to retorque my arp studs and decided to pull my plugs at the same time to check them out. Two were completely soaked in oil. Pulled the head off and what do you know, the valves were covered in oil and the pistons were covered in chunks of burnt oil.
Guy who did the machine work for my head ****ed up the guides big time. He actually reamed them out so the valve stem just kind of floated letting oil by. He also pressed them in way deep so they would always be submersed in oil.
He is going to wake up and find a nice surprise one day.

09-01-2006, 10:24 PM
well usually it would mean bad rings, bad valve guides, or bad valve seals. My car actually had oil on the spark plug but only in the middle and close to the end of the threads. You guys got me scared now. I did a compression test and the result was 160 across the board.

I know people say to do leakdown tests, but I thought a leakdown test was only needed if compression was bad?