What Does It Mean When Oil Is On All Of The Spark Plugs On One Bank Of Cylinders

Posted in Internal Engine Parts | Asked on Jun 15, 2010

I have for the oil-electrode part of my spark plugs (the part that is actually inside the cylinder) and all connectors on one bank of cylinders affected, whereas the others are in order. I suspect my already valve cover gasket has an external leak, but I think the problem with the plugs could be something to do with the cylinder head gasket have. Odds are not worn rings, because the plugs are on the other side perfectly, while the plug on the affected bank are all equal wet. My coolant overflow tank reservoir contains absolutely clean, pristine coolant, which is promising but not confirm, nothing. I have already bought a full set gasket for the valve cover, but I wonder whether I should go further and replace the head gasket while I’m at it. Would you like to receive oil from the interior of the cylinder, if the part of the valve cover gasket that surrounds the spark plug is bad? I know it’s a piece, and perhaps it was a blowout of the species. Is there a way to tell before I start cracking open the engine? Compression test? I really hope it’s just the valve cover gasket, but I will go and pick up a head gasket if that is what seems to be the problem. Come to think of you, it may, on the upper half of the dowels were also oil. I have no problems with coolant, however, had suffered from loss of oil. I seem to have convinced me that there is a bad valve cover gasket, so please confirm either this term or inform me otherwise. Thank you! Ok, wow, thanked all those previously written. Lots of good information from everyone. What I am now is to believe that some oil had collected over the threads of the plug, while the electrodes free of oil, that is, until I unscrewed the plugs, the oil allowed to run out the threads and coat the electrodes. This seems sensible that I have the problem by installing the gasket set that I had to resolve. Can anyone confirm this?

There are 6 Answers for "What Does It Mean When Oil Is On All Of The Spark Plugs On One Bank Of Cylinders"

  1. tech10 says:

    I am 99 percent sure it would be a valve cover gasket, otherwise you would have other Performance problems if was a bad head gasket. Changing a head gasket is a very major project, I would never change it just because I have the parts.

  2. bigdawg says:

    It could be your oil return galley is plugged not letting the oil drain back to the crank case.That would flood the valve cover could over power the valve seals and cause your valve cover to leak to

  3. dickfaberracing says:

    the definitive test for the head gasket (and the rings as well) would be a leakdown test. this is a compression test where the cylinder filled with compressed air and the amount of leak is measured. often the leak can be heard, and traced back to where it is.
    were the heads done up? its unlikely but it may have lost all the inlet valves stem seals in one bank. i have had a ‘reconditioned’ head come back with no seals fitted were the other was done correctly. it pays to be really anal (fastidious) when doing engine work done out of your sight
    it could also be a manifold gasket gone underneath, but this would also show itself as a lean out on that bank. this leads to the question of is the manifold matched to the head/or has the head block surface been machined not level? if the head is not machined level, it changes the angle where the manifold mounts. its unlikely but it has happened before
    also check the pcv valve. it its rooted, it may be spewing oil into the inlet tract
    also check the booster vacuum port in the manifold. if the brake booster has died, it can alloy the manifold vacuum to pull the brake fluid back to the engine

  4. the_boy_toy says:

    I doubt it’s your head gasket as only coolant is involved in that area. If you do have oil on the top half of the plugs then it could either be the valve cover gasket or a faulty PCV valve if it is equipped with one.

    Edit:
    Yes, if you do replace the valve cover gasket and it stops the oil from accumulating on the tops of the spark plugs then problem solve. If not post again

  5. Harley G says:

    The valve cover gasket seals the valve cover to the cylinder head. It’s impossible for a failed valve cover gasket to allow oil Into your cylinders. A failed valve cover gasket WILL however allow oil to get into your spark plug chambers, covering the spark plug – but NOT the electrode. Are you burning oil ? i.e. blue smoke from the exhaust?
    Oil in the combustion chamber is from worn piston rings, a blown head gasket or worn valve stem oil seals.

  6. bandit_60 says:

    if the oil is on the firing tips then you have bad oil rings on that side or valve seals. it,s also possibly could be the drain holes are clogged up under the valve pan too. pull the valve pan off and if looks like a river there then take a piece of wire, a coat hanger will do, and run down through the drain holes. you should have 2 holes. 1 on each end of the head.