A/C Issue

Discussion in 'Engine' started by steveoelliott, Jun 27, 2014.

  1. steveoelliott

    steveoelliott Hardcore MB Enthusiast

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    CLK 230K W208
    Hi all,

    My car: W208 CLK Cab.

    My A/C seems to be running very weak of late and to be fair I've not used it for a month or so since I've opted to have the hood down. Yesterday I noticed it was barely cold but perhaps just working.

    Looking on here I found out how to do some diags on the climate control panel and established that the temperatures reported are feasible. The question I have is around the Freon pressure (option 7). Mine reads 6/7 when idling on the drive with A/C running for several minutes. Does this mean it is low? I seem to recall it was only re-charged a couple of years ago.

    Incidentally at the same time I did a fault code check and it reported B1423 which apparently means a switchover control valve. Now, searching on here this may be related to my other problem with the centre vents not working most of the time. Is this a simple thing to just swap out?

    Thanks...
     
  2. lexman8

    lexman8 Hardcore MB Enthusiast

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    CL500
    Normally the pressure reading for Option 7 would be about 6 or 7 bar with the engine off. With engine and aircon both on, it should be about 14 bar so it would seem that the pressure is too low. Usual cause is lack of refrigerant but it could be something else.
     
  3. OP
    OP
    steveoelliott

    steveoelliott Hardcore MB Enthusiast

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    Thanks....

    Some folks say the compressor / condenser are common failure points on the w208. What are the symptoms of these failing?
     
  4. lexman8

    lexman8 Hardcore MB Enthusiast

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    Compressor failure would be indicated if it doesn't raise the pressure to allow the system to cool sufficiently. It can fail internally or the clutch (if fitted) can also fail. A condenser failure is pretty much always a leak, often caused by a stone or other object impacting it. The condenser is normally the front radiator that you can see, with the engine cooling radiator behind it, nearer the engine.

    If your system continues to hold the same pressure for over a week or so it's probably not a leak or it's a very small one.

    There are other possibilities such as wiring/control unit problems. It may need to go on STAR for a better diagnosis.
     
  5. markjay

    markjay MB Club Veteran

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    Did you check the temperature at the vents?

    [​IMG]

    [​IMG]
     
  6. Major774

    Major774 Hardcore MB Enthusiast

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    Mine goes into the 4s and my father's W210 can hit into the 3s.

    The W210 is 15 years old (owned from new), never had re-gas before and is still cold lol
     
    Last edited: Jun 27, 2014
  7. OP
    OP
    steveoelliott

    steveoelliott Hardcore MB Enthusiast

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    CLK 230K W208
    Thanks guys... I think first things first is to take it for a re-gas... They check for leaks using a vacuum and would also be able to advise on the refrigerant level.

    If they advise something is wrong or it still isn't cold then I can look at taking to a specialist.
     
  8. Lyserman

    Lyserman Hardcore MB Enthusiast

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    A cautionary tale. I had mine re-gassed at ATS and their machine said it was fine, no leaks. It stopped working again shortly after.
    I got a mobile specialist to look at it and he found a leak on the high pressure connection on top of the drier that the automatic machine did not detect. He fixed it and re-pressure tested then vacuum test and re-charged the system. It has been nice and cold in the car since.
    If you have a suspected leak then I would recommend getting an air-con specialist to carry out the work and not just trust the automatic machine.

    Tony
     
  9. OP
    OP
    steveoelliott

    steveoelliott Hardcore MB Enthusiast

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    CLK 230K W208
    Good news...

    I had my A/C checked by a recommended mechanic who checked with a dye that there was no leaks and re-filled. Apparently it was nearly empty!

    My Freon / refrigerant now shows 15 when A/C running instead of 4.
     
  10. OP
    OP
    steveoelliott

    steveoelliott Hardcore MB Enthusiast

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    Although, my centre vents are still a problem but they always have been for me. I understand this is to do with some pipes behind the dash and it will probably be more hassle than it's worth to fix.

    But... at the start of this thread I did mention a fault code which my climate control reported: B1423 which apparently means a switchover control valve. Could it be just a simple case of swapping this?
     
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