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w211 E320 Alternator removal

Discussion in 'Electrics, Vacuum, Ignition and ECU' started by DY2, Dec 2, 2012.

  1. DY2

    DY2 Senior Member

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    Your Mercedes:
    W211 2003 E320 Cdi Automatic
    W211 Alternator removal – 2003 ‘03’ E-Class 320

    I have done this recently, and thought I would do a write up or those who may come into this situation in the future.

    I put a new battery in the rear of the car, as I was getting the “electric consumers switched off” malfunction appear. But this didn’t care my problem. Checking the voltage through the battery, it was clear the alternator was not doing its job of putting charge back.

    I decided to put a new alternator in.

    Just a note, I also replaced the drive belt and coolant, as you have to remove two water pipes to the water pump, and you’ll lose coolant.

    On advice from others and their past experience. I always open the driver’s window fully, or have the spare key handy. I’ve heard plenty of stories regarding keys being locked inside the car when you reconnect the battery.

    This is what I done:

    Jack up the car, front driver’s side. Remove both of the under trays – This is to access the two bottom bolts on the alternator.


    1. Open the boot, and disconnect the negative feed to the battery.
    [​IMG]

    2. Open the bonnet, and passenger side, at the rear, undo the black screw and remove the pollen filter.
    [​IMG]

    3. Under the pollen filter, you will see the smaller battery for the SBC, again, disconnect the black negative feed.
    [​IMG]

    4. Take a sketch or a picture of the drive belt for when it comes time to put it back on
    5. Undo and remove the black/ grey engine cover.
    6. Remove the air intake pipe, by pinching the edge near the air filter then wiggling away from next to the radiator
    [​IMG]

    7. Disconnect the electrical connection to the MAF, loosen the jubilee clip.
    8. Remove the round circular pipe connected at the MAF, there is a small tube to pull, an electrical connector and another jubilee clip to loosen underneath, then pull this out.
    [​IMG]
    9. Under the car, disconnect the two electric cables attached to the alternator. You can then, from the top of the engine pull this up and out of the way.
    10. Loosen the jubilee clips holding the two pipes into the water pump ( I used cable ties to secure these against the SBC pump), this is where you will lose the coolant, if you can place a bucket or sort under the car to collect it. You will lose a few litres.
    11. Below the two water pipes, is another black rubber pipe. Disconnect this and remove.
    12. Now to remove the engine fan. This is need to give sufficient space to remove the alternator and get the new one in place. There are seven bolts and two torx screws to remove on the center crossbar. Lift up and fold over the crossbar, there is a cable underneath which can be loosened to allow the crossbar to fold over completely.
    [​IMG]

    13. At each end of the fan, there is a clip - remove these using a flat headed screwdriver. Disconnect the electric connector at the side of the fan (passenger seat side). You will also have to move about some pipes at the bottom of the fan, I used extension bars from my socket set. You can then wiggle out the fan from the engine.
    [​IMG]

    14. Move the tensioner pulley and use an allen key to lock the tensioner in place. Remove the drive belt.
    15. Now you should have clear access to the alternator. There are 3 top bolts and two bottom bolts, use a 10mm socket bit or spanner to remove these.
    [​IMG]

    16. The alternator can then be removed out the top of the engine.
    17. Put the new alternator in place, lining it up carefully with two longer top bolts, then the bottom two bolts.
    [​IMG]

    18. Once it is in place and secured, put on the new drive belt.
    [​IMG]

    Then working backwards, reinstall all the parts removed. Once complete - refill the coolant tank. Reconnect the batteries (It may be wise to recharge them).

    Hopefully, when starting the car, you should get no more warnings about the electric consumers switched off. Mine has been done a week now and no malfunctions.

    [​IMG]
     
    Ed Harrald and Davefo like this.
  2. anyweb

    anyweb Senior Member

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    great post, keep it up !
     
  3. G-a-r-y

    G-a-r-y Senior Member

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    Your Mercedes:
    S211 320 CDi, SLK 200 R171.
    Good post and pictures.
     
  4. spenttherent

    spenttherent Senior Member

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    E350 Bluetec 2013
    Thanks for this post I think I'll have to do the same job myself.............I'm interested in what voltages you were getting to determine a new alternator and what you are getting now
    Thanks Again
    Graham
     
  5. television

    television Always remembered RIP

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    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    Around 14 volt with engine running is correct.

    With any 2 battery system it is important to connect the batteries in the correct order.

    The rear one must be connected after the small one up front.
     
  6. OP
    DY2

    DY2 Senior Member

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    Your Mercedes:
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    Now with a working alternator, I am getting 14.0-14.1v with the engine running.
    With the engine off, A battery should be about 12.5v roughly.

    Before the battery wasnt getting the rechange, so I was constantly getting the "consumers switched off" malfunction when starting the car, then as the battery was draining, i was getting other warnings, such as ESP, ABS, and brake defective (RED) malfunctions.
     
    Last edited: Dec 5, 2012
  7. spenttherent

    spenttherent Senior Member

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    Thanks for that TV I've got 13.9v when my engine is running with everything off but only 13.5v when the heater fan is on, I've fitted a new brush and reg pack I am now thinking it is a pully problem as it doesn't fully charge my new battery
     
  8. television

    television Always remembered RIP

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    Is this measured directly over the battery. what is the voltage when turned off
     
  9. television

    television Always remembered RIP

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    I do hope this post has gone into the DIY section, a terrible waste if it has not
     
  10. spenttherent

    spenttherent Senior Member

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    I get 12.2v when turned off.......thats on the dash readout
     
  11. television

    television Always remembered RIP

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    OK, now this is not that accurate, and you could be chasing a red herring.
    The must be a PD over any wires and a voltmeter must be used for any worthwhile reading. You have changed the reg pack, so that is good. the belt would be screeching away if there was a problem there.

    Now if the battery is not holding its charge, could there be a drain somewhere ?? Is the battery past its best.

    Why do you think it is not charging correctly
     
  12. spenttherent

    spenttherent Senior Member

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    I've just used a voltmeter and there is 13.9v at the jump pin and 13.8 at battery when the and lights and heater are on it goes down to 13.4-5v……I bought a new battery 12 months ago which wouldn’t fully charge over 12.2v even if I disconnected it after a long run and got a reading in the morning and the “electric consumers switched off” message kept appearing. When I took the battery back to where I bought it they told me my alternator voltage was low and that it didn’t increase when I revved it that’s what makes me think it’s the freewheel pulley freewheeling the wrong way. I have now got a new battery and I am worried that’s going to go the same way
     
    Last edited: Dec 6, 2012
  13. television

    television Always remembered RIP

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    The free wheels only go one way, so not that. it is known that on the 211 and the 230 with dual batteries, that if the cars are only used every now and again, or for very short runs the battery will need a top up. When you turn these cars off they take a while to go to sleep, and the current can be quite high if the comand has been turned on.

    The is an update for the soft ware on a 211 where this consumers off message is shifted, and this can make a big difference, one can also have a door controller leaking and the standing drain too high. it should not be anymore than 55ma, with a controller leaking this can rise to some 150ma and the battery will drop down to the 11.75 volts where the consumers get turned off
     
  14. spenttherent

    spenttherent Senior Member

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    Thanks for the reply TV....... I'll give it top up now and again and see how it goes

    Cheers
    Graham
     
  15. mattuk

    mattuk Senior Member

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    Nice diy!
    One thing which could be add are arrows pointing where and what exacly you do. However good job! bravo
     
  16. Ed Harrald

    Ed Harrald Member

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  17. Ed Harrald

    Ed Harrald Member

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    Hi. Many Thanks for your Photo's And Very Informative, Step by Step, Guide to Replacing An Alternator on an E/class 320 CDI !!
    I have just spent a frustrating couple of weeks, with exactly the same problem as yourself, and am now faced with having to replace the Alternator !! After viewing the American doing it on You Tube, It looked a fairly simple job (Wrong) He makes no mention of having to remove the Belly Pan, and having to work underneath, which suited me, Having a bad Back at the moment !! Although it was stated that he was working on an E320, 2003 model, the same as mine, once I got started, (without the use of a Ramp) it became very noticeable, that the Alternator mounting bolts, on his were totally different to mine !! Your Description has educated me, that there are Two more mounting bolts, accessed underneath, that the American's didn't have !! So bad back or not, I have got to venture underneath to release these!! Perhaps somebody can inform me, if there are any fastenings to undo for the Fan Shroud Underneath as well !!
    Meanwhile Thanks a Million, for your Informative Post !!
    Regards Eddie.
     

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