Mitsubishi Repair: plug holes, valve cover gasket, plug holes

Question
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Followup To
Question -
i have a 1998 mits. eclipse RS with an auto tranny. it has a stock 2.0 l motor. ok i have oil in my #4 plug wire hole on the motor. i have changed the plugs and wires. still the oil is there. it runs smnooth but feels down on power a little. a few times ive looked and -no oil then i look and its about 1 inch deep with oil. what is going on, where do i start, what how do i test....HELP.   it has 75,000 trouble free miles.
         RON
Answer -
Ron,
You may have a leak in your valve cover gasket.  There are 4 seals that fit around the round spark plug wells.  Overtime, those seals can harden and they don't form a good seal.  Oil can leak past the seal and cause oil to pool up around your spark plug.  All cars will require a valve cover gasket change at least once in it's life.  Another thing which should be replaced on an annual basis is your PCV valve.  It's located on back of your valve cover.  That valve relieves pressure under your valve cover.  If that pressure is not relieved, it can force oil to leak through weak points in your valve cover.  The PCV valve only cost about $5 and takes about 5 minutes to replace.
Good luck!


   Anthony,
      I just replaced the valve cover gasket and tested mypcv valve which is ok. I still have oil in that hole. I have noticed that my plug wire on the ignition point for that cylinder sometimes feels like its not on all the way could a weak spark have anything to do with it?  is there anything else it might be?
         Thank you for your time,
         -Ron-  

Answer
Ron,
A weak spark would just prevent the cylinder from firing as it should.  It should not cause oil to pool up in the well.  You would just feel a signifigant loss of power upon acceleration.

Hopefully you checked for cracks on the underside of your valve cover when you took it off to replace your valve cover gasket.  The valve covers are aluminium and tend to crack very easily if the surrounding valve cover bolts are over-torqued

The pooling of oil can also be caused by piston rings or cylinder walls that are badly worn. Oil may also be pulled into the chamber because of excessive clearance in the valve stem guides, or badly worn valve stem seals.  If this was the cause, you may need a head rebuild and/or new piston rings.  Both jobs are pretty expensive; mainly because they are extremely labor intensive.  I'd recommend having your compression checked in that #4 plug well.  If the compression is to low, that would reveal evidence of worn stem seals, rings, or head gasket.
Good luck!