oily plug discovered

May 19, 2008 4 Replies

I was in the process of swapping some NGK iridium's in my '05 c230 k



4dr. sport when I discovered no. 2 plug came out completely covered in oil with oil showing at the bottom of the thread hole. All other plugs were dry. Buttoned everything up without swapping new plugs and checked the oil level read out. Days before I had completed a spring oil change. Oil level checked out as normal. Started the engine as before with no indication of any problem. What is happening here.

Now, when you said oil on the thread. I am assuming no oil on the electrode. That is common on modern engine as there are many seals on the valve cover... oil will seep past the oring and collect at the spark plug.

If the car is still under warranty, have them do the warranty service on the valve cover gaskets.

Why did you change the plugs? What mileage do you have on the car now?

The car had been sitting idle for the past 4 days since the oil change. With plug in hand, oil present from tip of electrode to top of thread and no oil present on coil pack stem or in plug cavity. Plugs # 1,3,4 no oil present. I choose to have a high maintenance practice, costly, but peace of mind, and I believe my cars appreciate that.

16650 miles. Car still under warranty.

Tiger wrote:

Cars don't appreciate anything, they are nuts and bolts put together on an assembly line by robots and a few illegal Turkish immigrants. Every time you fiddle with it is one more chance of something getting screwed up. I drove my 928 from 1990 until 2006 with only 1 oil change and 1 timing belt, it was still running fine when the lady putting on makeup totalled it at a stop sign.

As for the oil, do not leave it in for more than 1 year... oil, metal and engine contaminant makes it acidic... so it is safer to change every year for those classics that are not driven often. Dino is fine in this situation.

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