I researched this once already, but can't find the thread that had some answers. Here's what's going on:

• Car running well, then starts missing, throws P0304 and P1316 code
• I'm figuring coil pack, but when I pull the # 4 coil pack out, the spark well is full of oil, and the spark plug is badly fouled. Seems to be a lot oil in the other wells also.
• I remember reading an explanation as to why oil in the plug wells could affect the coil packs, but can the oil seep into the cylinders and contribute to plug fouling?
• Finally, when the car sits overnight after driving it on a long trip, I get a cloud of blue smoke when I start it up the next morning. It's also using a fair amount of oil. I've been blaming bad valve seals as a cause of the smoke on morning startup, but could oil in the plug wells be the real problem?

Thanks,

 

Engine oil in the spark plug wells occurs due to perished seals. When the coil units become fouled with oil, they short causing misfire(s) to result. Misfire(s) can damage the catalyst(s) with eventual DTC P0420 or P0430 being set.

Oil fouling of the spark plug electrodes is caused by faulty valve seals or worn piston oil control rings.

 

The oil in the plug wells comes from leaking cam cover gaskets. Since this is a recent occurrence you most likely have a plugged part load breather. It can plug at the cam cover and anywhere along the tube. At idle engine and under acceleration vacuum level is very high. Normally the part load breather would vent the vacuum to the intake where any engine blow by and crankcase pressure would be vented to the intake.
Since blow by pressure is building up it then causes cam cover leaks, oil blow by at pistons and fouling of the plugs. The first step is to clear out the part load breather. With the line removed the fitting on the cam cover has a small orifice that you will need to clean out with a small drill bit or awl. Then make sure the breather tube itself is clear. Clean all of the oil out of the plug wells, clean and dry the boots and put it all back together. Drive for a short time and monitor the plug wells, if they persist in leaking then the gaskets are damaged and you will need to replace the cam cover set.

 

Thanks guys, i guess my first instinct was correct; bad valve seals. I'm having an unusual problem with the cylinder # 3 spark plug. The socket just spins on it without engaging the flats. Did the plug shrink, or did some idiot put some weird-assed plug in there?

 

 

I wasn't aware of a spark plug socket smaller than 5/8". I'm going to change the cam cover gaskets and seals and I'll have a better view of the plug when the cover is off. Who puts two different size spark plugs in an engine?

 

I had that problem on my Z4. It was the rubber ring from a plug socket that got stuck on the plug. Shine a bright light in there to make sure you don't have the same problem.

 

Quick question... What's the best way to clean all that oil out of the spark plug wells?