CL 420 tappy tappit

Discussion in 'Engine' started by Bechstein, Aug 16, 2011.

  1. Bechstein

    Bechstein New Member

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    Car:
    1997 CL 420
    New to CL420 ownership and new to the forum so please bear with me.

    The CL420 in question is a 1997 model that has covered 84,000 from new and during the last four years it has covered in the region of 1000 miles a year.

    I have seen similar threads concerning disintegration of the oil feed pipe to the tappits and will investigate however my first course of action was to flush the engine with a Wurth engine flush and fill with a premium 5w40 fully synthetic oil.

    This quietened the noise considerably although it's still irritating with all windows and roof open which is how I like to drive (weather permitting).

    However I noticed in the service history that it has been filled (by Merc) with Duckhams initially and then with Shell Helix and am wondering if my choice of oil was wrong.

    Also, is MB the only source of valve gear if replacement parts are needed?

    Thanks in anticipation.
     
  2. grober

    grober MB Master

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    It's possible that the previous owners choice of oil or frequency of oil+filter change was in error rather than yours. A 5w40 fully synthetic should be fine for your engine. The 420 engine of that vintage was rumoured to be harder on its valve gear than its 500 cousin but I would have thought their valve trains to be identical?? Maybe the 420 uses a bit more RPM's routinely or there's a bit more valve lift in the cam profile -- don't know?:dk: It may be a sticky/worn /blocked hydraulic tappet which needs replacing or the problem may be more widespread. I would go to MB for the parts. Be sure to check all these ancilliaries at the front of the engine driven by the poly V belt -especially the tensioner assembly to make sure that noise isn't coming from there.
     
  3. flango

    flango Hardcore MB Enthusiast

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    If it's the M119 engine I would not put fully synthetic anywhere near it as there have been some compatibility issues when using fully syn in late 1990's cars. A semi syn 10w-40 would be fine, Shell Helix would be my preference.

    As Grober says check all the ancilliaries on the front end just to rule these out, worn tensioners can create a sound very like that of rattly tappets.
     
  4. jaymanek

    jaymanek Authorised Forum Sponsor Authorised Forum Sponsor

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    You need to change those oilers... They are cheap to buy and not a massive job to fit either.
     
  5. jonnyboy

    jonnyboy MB Enthusiast

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    Agree with Jay, easy job if you do them one/two at a time.
     
  6. OP
    OP
    Bechstein

    Bechstein New Member

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    Aug 16, 2011
    Car:
    1997 CL 420
    Thanks!

    Many thanks for your tips and advice.

    I have a 200 mile trip to do in the car in the not too distant future.

    Will I cause any long term damage by doing this before I do the repair?

    Judging by the service history this has been a issue for the last few thousand miles.

    Paul.
     
  7. OP
    OP
    Bechstein

    Bechstein New Member

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    1997 CL 420
    Oilers changed and noise gone, although to be honest, the oilers that I removed looked like new.

    Good advice over the phone from Jay.

    Many thanks,

    Paul.
     
  8. jaymanek

    jaymanek Authorised Forum Sponsor Authorised Forum Sponsor

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    well done, satisfying eh!
     
    1 person likes this.
  9. parina

    parina New Member

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    Hi, does anyone have the MB part numbers for the oilers?
     
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