My 1995 E320 (237K miles) started running rough. I pulled the spark plug wires out, and found oil on the connectors for cylinders 3 & 4. The plugs for 3&4were oily. I replaced all six plugs, and the carran smooth for 1/2 mile before running rough again. Will a simple replacement ofthe head cover gasket correct this, or will it require a more expensive head gasket replacement?

 

Hello, I have a 1998 E-320. Experienced the same problem a year or two ago. Cylinder 2 plug kept fouling. I replaced both sides of the valve cover gasket. I also discovered that the plastic piece (neck ) oil filler was also leaking. I could of just replaced the gasket, but it seemed the plastic neck looked old and worn. It was a dealer item around $18.00. Both sides of valve cover gaskets around $44.00. I laughed when I saw they where made in IRELAND!. I would give the job a medium to easy in DIY terms. Remember to make sure the gasket does not pinch or roll.
It cured my plug problem.
Honestly, and I 'am not trying to say it is. But if you cannot see the gasket leaking, I would do a compression test first on the cylinder BEFORE you go into the removal and replacement of the valve cover gasket. Hope this helps! Good Luck

 

silentwatchdog00: Thanks for the info. I really appreciate it. I was planning to forge ahead with the valve cover gasket replacement to see if that worked before taking it to the shop.After my first oil changewiththis car, oil was leaking from the oil filter housing. Not too badly, but just enough to smell it. I found that the old o-ring had become flattened in the groove of the housing cap to point that I couldn't tell that I was putting a new o-ring right on top of it. After realising what was going on, Iremoved the old, flattenedo-ring out with a knife, and problem solved. Hope that you're having a great holiday season.

 

For anyone who needs advice on the same problem: I changed the spark plugs (Bosch Platinum +2 @ $30 for set of six) and thevalve cover gasket (OEM @ $20)first. I found that the oil around the spark plug wire connectors had fouled the connectors. Car was still running rough. I replaced the spark plug wires (Bosch @ $105). Car runs like a top again, and no oil on the spark plugs after a day of driving. Total cost of parts was $155. About 3 hours of my labor. Man, I feel handy!!!