W220 V8 spark plug replacement

Discussion in 'Engine' started by 944S2cab, Oct 10, 2019.

  1. 944S2cab

    944S2cab Member

    Messages:
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    Nov 11, 2015
    Location:
    Ribble Valley, Lancashire
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    1999 W220 S430
    Having just changed the 16 spark plugs I can offer a few tips for anyone contemplating this job.

    1. Shop around. I obtained 16 Bosch spark plugs for £80 from Eurocarparts on ebay.
    2. Allow plenty of time for the job. You do not want to be cross-threading a spark plug by rushing. It took me over half a day.
    3. Don't try and do the job with the coil packs in situ. You need as much working space as possible. They are held by a single screw. Move them out of the way. When refitting, the upper plug lead goes to the plug in front.
    4. I dropped 2 spark plug sockets, an extension bar, 2 coil screws and a magnetic retrieval tool into the engine bay and I could not see them from above. Either put an old bed sheet or similar between the engine block and the inner wing, or remove the 2 engine undertrays to allow things to fall onto the floor and be picked up.
    5. The metal plug lead caps were well and truly stuck on the spark plugs. I tried a number of tools to remove them. I had to resort to a large pair of water pump pliers to move them.
    6. Access is the big problem. I could not see most of the spark plugs and had to work by feel. A small inspection mirror will be useful with a small powerful torch. A decent socket set is a must, and one or more palm-spinning ratchets will be helpful in tight spots. Use a 5mm length of slack-fitting hose on the plugs to get them started; this will prevent you cross-threading the plug when you can't see what you are doing.

    Good luck!
     
    stwat and Abb like this.
  2. greenmanslk

    greenmanslk Active Member

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    And owners complain at the cost MB charge...
     
  3. johnsco

    johnsco Hardcore MB Enthusiast

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    Yes - and I had a year 2002 E430 (W210 face-lift).
    Exactly the same issues ...
    A plug change is not for the faint-hearted !!
     
  4. Will

    Will MB Club Veteran

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    I don’t think it’s quite as bad as it sounds in this thread. A little fiddly and time consuming but a relatively easy and straightforward job if you take your time :)

    I would add, a small 17mm open ended spanner is the perfect size to pop the leads off without damage.

    Compressed air to blow any dust/debris out from the area surrounding the plugs is a good idea before you remove them. Saves dust/dirt falling into the cylinders or onto the threads.

    I never use anti-seize compounds on plugs. Not a good idea imho, MB don’t specify it either. It can dry out and gum up/go sticky actually causing plugs to be more difficult to remove in future. Clean threads are important though. Sometimes worth cleaning the threads on the old plugs and running them in/out carefully if they are dirty

    Use a torque wrench to tighten to spec once refitted.

    Even if you spend half a day doing this it will probably save you £££ that you may wish to spend elsewhere. Quite satisfying and simple to do, just take your time :cool:
     
    C43AMG likes this.
  5. IanW

    IanW Hardcore MB Enthusiast

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    W209 CLK 500
    And a couple more (based on my experience with the W209 engine bay):
    - When removing the coil packs, label them. The ignition lead length varies.
    - My spark plug socket is a good fit into the hole in the head. Insert the new plug into the socket first, then use that to insert into the head. No chance of cross threading as the socket presents the plug squarely into the head.

    "I would add, a small 17mm open ended spanner is the perfect size to pop the leads off without damage."
    Second this. It's even better than the special tool I bought in the States.

    Ian
     
  6. robparker

    robparker Active Member

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    taunton
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    Also, just buy the plugs from MB, the price is nigh on the same, then you have a nice receipt for your history file rather than a euro one
     
  7. DSM10000

    DSM10000 MB Club Veteran

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    If it is a spark plug from a reputable make and as recommended by MB what difference does it make? MD do not make spark plugs.

    When I needed plug s for my C320 MB were twice the price of ECP with one of their regular discounts.
     
  8. johnsco

    johnsco Hardcore MB Enthusiast

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    I got the 16 Bosch plugs for the E430 from Euro.
    As said ..... About half the price.
    Every little helps !
     
  9. OP
    OP
    944S2cab

    944S2cab Member

    Messages:
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    Joined:
    Nov 11, 2015
    Location:
    Ribble Valley, Lancashire
    Car:
    1999 W220 S430
    I tried a 17mm open ended spanner on the plug leads but it would not move them. Nothing else worked, hence the water pump pliers.
     
  10. Major774

    Major774 Hardcore MB Enthusiast

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    An 18mm spanner works better, more leverage.
     

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