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Oil found on my spark plug, that cant be good

jeramie1jeramie1 Member Posts: 6
edited March 2014 in Chevrolet
couple of months ago on my 94 Chevy full size P/U and today, when I was changing the PCV valve I noticed one of the plugs had oil all over it. So, what could that be? I have noticed myself needing to add more oil in between oil changes, I guess I found my problem. This is going to hurt my wallet, isnt it?


  • bnosytbnosyt Member Posts: 23
    If it is on the outside of the plug, I would suspect it is just the valve cover gasket that is leaking.
  • andre1969andre1969 Member Posts: 25,666
    ...probably the valve cover gaskets. How many miles do you have on your truck? Also, sometimes when a PCV valve goes bad, if it starts getting loose, it can spew oil. I had a '69 Dart GT that did this.

    Valve cover gaskets really aren't a big deal, and on a full-size Chevy, should be fairly easy to do. I'd guess $100.00, tops. You might also want to see if the valve covers just got loose over the years. You can test this by checking to see if the bolts holding it down need to be tightened. Just don't over tighten them or, worse, break one off! Then it WILL leak, and make a mess! I learned this with a friend's 1976 Hornet wagon!
  • mrdetailermrdetailer Member Posts: 1,118
    or is the oil just on the outside?
  • adc100adc100 Member Posts: 1,521
    (screwdriver with hex-no tighter) Go around a couple of times.
  • jeramie1jeramie1 Member Posts: 6
    nut driver, oh Andre, I have 105k on her, Mr.Detailer, I will look at the plug tomorrow to see if it is also fouled, I suppose it is bad if there is oil on the inside of it also. Could it have something to do with me changing out the old plugs?
  • jgmilbergjgmilberg Member Posts: 872
    On that year truck there are only four bolt holding the valve cover down, and according to Chiltons you tighten them down firmly. The bolts are in the center of the valve cover 10 mm I think. Not to involved to change them yourself, they are made of rubber, and it does get brittle and crack over the years, so my choice would be to just change them instead of just tightening, in my experience if a rubber gasket cracks when you squeeze it it will separate more increasing the leak. Gasket set should be around $25, and it will take 1-2 hours depending on your skill level, and emissions stuff that may get in the way.

    One more tip, NEVER USE SILICONE ON RUBBER GASKETS!!! It will cause it to leak every time, trust me. They are designed to seal against a clean oil free surface with no need for silicone.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Not only that, if you splurge with the silicone, it can get into the engine oil and create havoc in your oil galleys.
  • cuda8cuda8 Member Posts: 2
    I changed the plugs on my 91 Chev Cavalier 4 cylinder station wagon and noticed oil on the lower part of plugs 1 and 2. Plugs 3 & 4 were dry. The plug gap on all plugs was nearly double the spec of .35.

    The oil pressure gauge shows 80 when engine running.

    Looks like some leakage around the valve cover. Any suggestions as to what the problem may be?

    The engine has 103,000 miles on it.
  • adc100adc100 Member Posts: 1,521
    Replace the valve cover gasket or try tightening just a tad. Its normal for the gap to get larger as the plugs get worn out. I assume they are not Platinum.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    that's an awful lot of oil pressure. I wonder if your gauge is correct. Too much oil pressure is not so good.
  • cuda8cuda8 Member Posts: 2
    Would like to do a transmission fluid change on my 91 Chev Cavalier but am unable to find a drain plug on the transmission pan. Any suggestions??
  • alcanalcan Member Posts: 2,550
    GM discontinued automatic transmission drain plugs in 1969. Place a large drain pan under the trans and remove the last couple of bolts slowly. Btw, why wasn't this posted in the "Transmission Trauma" forum?
This discussion has been closed.