World War III and spark plugs

Discussion in 'Engine' started by Stringer, Aug 30, 2013.

  1. Stringer

    Stringer Active Member

    Messages:
    144
    Joined:
    Sep 16, 2012
    Location:
    Lebanon
    Car:
    300E 1987
    Dear esteemed members
    there is a bloody massive war here about to kick off, which is a bit of a bugger as i haven't resolved the conundrum of why my plugs are ever-so-slightly oiling up and eventually misfiring.
    There is no significant loss of oil. And no blue smoke. But if i go on a long journey of say 30 miles, for sure one will start missing.

    I just bought a compression tester and tested the pots. They were all between 175 and 200.
    Can i assume from this that it is the valve stem seals which are shot?

    And if so, would STP help? Or 'high mileage' oil which is relativly new on the market?

    thanks
    M in Beirut
     
  2. E55BOF

    E55BOF MB Enthusiast

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    Location:
    South Bucks
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    SLK55, ML420 CDI, FJR1300, Caponord
    Compressions sound good, but that doesn't necessarily mean the oil control rings are 100%. I assume it's not one particular pot which misfires? Could be the valve stem seals, but in my (general - I know nothing specific about your particular engine) experience, that would give a puff of blue smoke on start-up.

    I doubt changing the oil to something thicker would help, but you won't know until you try it. Changing to a hotter-running grade of spark plug could well help, though; a hotter-running plug will burn off slight oil deposits more readily. This has nothing to do with outside temperatures, by the way, and will not raise your coolant temperature. What plugs are you using at the moment?

    If hostilities do break out, I wish you all the best, but regrettably, we can't affect that side of things.

    E55BOF (42 years of bodging...)
     
  3. Tinkerer

    Tinkerer Active Member

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    W210 E220 CDi
    You really need to post the mileage of your car together with wet & dry compression figures to get a true evaluation. A 1987 car may also have experienced embritlement of the valve stem seals which may give rise to the problem.
     
  4. grober

    grober MB Master

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  5. OP
    OP
    Stringer

    Stringer Active Member

    Messages:
    144
    Joined:
    Sep 16, 2012
    Location:
    Lebanon
    Car:
    300E 1987
    Thanks for all your replies and concerns. To answer E55's question, yes it is not one particular pot whose plug fouls up. I changed the plugs to a hotter burning Champion plug which seems to have made quite a difference in the respect that i can at least drive 30 miles on the hhighway before one plug starts missing - whereas before with teh Bosch nornal plugs, they would oil uo after 10 minutes of being in traffic.
    The car's mileage is about 150,000 miles to answer another question.

    But if it is the valve stem seals, wouldn't it be easier to get some of that new-fangled 'high mileage oil' which is designed to close the gap on ones seals?
    I noticed no one made a comment about STP. Perhaps i would have got more takers if i had made the question about STDs.
    Shup up stringer. Is that the noise of an Israeli jet i can hear or the air conditioning system making its normal racket?

    I will see if there is a puff of smoke on start up. If not, then what the blue blazes can it be, other than rings starting to go?
     

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