w124 engine wine on start up (lasts 30 seconds) then fine

Discussion in 'Engine' started by The Boss, Oct 13, 2011.

  1. The Boss

    The Boss MB Enthusiast

    Messages:
    3,524
    Joined:
    Dec 10, 2008
    Location:
    private!
    Car:
    private!
    any ideas what this is?

    only lasts 30 seconds from first start up, and then settles down.
    cheers

    [YOUTUBE]yqQeQKywRyc[/YOUTUBE]
     
  2. grober

    grober MB Master

    Messages:
    27,863
    Joined:
    Jun 22, 2003
    Location:
    Perth, Scotland
    Car:
    W204 C200CDI Estate
    Its probably the charging load on the alternator. It usually pushes out high current for a few seconds after a start to top up the battery. Battery voltage comes back up--- charging current goes down -load on alternator is reduced- sound disappears. Probably a reflection that the battery isn't charged up quite so much on these colder /darker days- nothing to worry about.
     
    Last edited: Oct 13, 2011
    1 person likes this.
  3. OP
    OP
    The Boss

    The Boss MB Enthusiast

    Messages:
    3,524
    Joined:
    Dec 10, 2008
    Location:
    private!
    Car:
    private!
    the battery was only recently changed and has had 20 miles on it in 2 months!

    could the alternator be needing a health check?

    cheers in advance
     
  4. Martyn_n

    Martyn_n Active Member

    Messages:
    612
    Joined:
    Nov 27, 2010
    Location:
    Leicester
    Car:
    W124 E320, ML270
    I'm assuming there is an attachment which I cannot hear on my work computer. With that in mind don't shoot me down for a stupid answer, but have you checked if the starter is disengaging properly. Can stay engaged if solenoid is dodgy or spindle is not lubricated corectly.
     
    1 person likes this.
  5. grober

    grober MB Master

    Messages:
    27,863
    Joined:
    Jun 22, 2003
    Location:
    Perth, Scotland
    Car:
    W204 C200CDI Estate
    I guess you could get a friendly vehicle electrician to put a clamp meter on to the ALTERNATOR output wire and watch the current - if the charge current subsides with the noise - you have your answer. It might mean the alternator front bearing is very slightly worn which means you hear it more under load but its nothing to worry about. Other thing to check would be that the alternator is charging adequately- might need a new regulator/brush pack- or your new battery might be duff. Quite few possibilities but really pretty normal behaviour unless it gets worse.
     
    1 person likes this.
  6. AMG19

    AMG19 Active Member

    Messages:
    114
    Joined:
    Nov 16, 2010
    Location:
    Surrey
    Car:
    500SL
    It' s the air pump.
     
    1 person likes this.
  7. grober

    grober MB Master

    Messages:
    27,863
    Joined:
    Jun 22, 2003
    Location:
    Perth, Scotland
    Car:
    W204 C200CDI Estate
  8. jaymanek

    jaymanek Authorised Forum Sponsor Authorised Forum Sponsor

    Messages:
    16,412
    Joined:
    Nov 29, 2002
    Location:
    Nuneaton Warwickshire
    Car:
    Lots of Mercedes!
    they all make that noise dont they?
     
  9. OP
    OP
    The Boss

    The Boss MB Enthusiast

    Messages:
    3,524
    Joined:
    Dec 10, 2008
    Location:
    private!
    Car:
    private!

    dont know.. been hearing it for the last year or so, only got round to publishing it now..

    it wasnt there in past years..

    does yours make similar noise?
     
    Last edited: Oct 13, 2011
  10. BillyW124

    BillyW124 MB Enthusiast

    Messages:
    2,890
    Joined:
    Oct 22, 2010
    Location:
    North West London
    Car:
    W124 E320 coupe, W211 E320 V6 CDI, W211 E63 V8 AMG, R129 SL 280 V6, W215 CL 600 V12 Bi Turbo.
    Mines makes this sometimes but only when i havnt moved the thing for a little while. It then goes away.

    This is known to be perfectly normal i am advised.

    A few 124's ive heard now make this noise upon start up.
     
  11. GP801

    GP801 MB Enthusiast

    Messages:
    2,905
    Joined:
    Jun 18, 2010
    Location:
    Sussex and Tuscany
    Car:
    2003 W209 CLK, 2005 R171 SLK in UK, 1995 S124 E280 in Italy
    Our 280 sounds very similar for a few seconds but not quite as loud as yours. Dont think its anything to worry about
     
    1 person likes this.
  12. AMG19

    AMG19 Active Member

    Messages:
    114
    Joined:
    Nov 16, 2010
    Location:
    Surrey
    Car:
    500SL
    Yes they do all make this noise I don't think you have anything to worry about.

    When you start the car have a look at the pulley furthest to the left(just above the alternator.) In the centre the nut will spin. When the centre nut stops spinning it will be the exact time the car stops making the noise. This will confirm without doubt it is the air pump.

    If it was the alternator why would it stop after 30 or so secs?? Doesn't make sense does it.
     
    1 person likes this.
  13. MOCAŠ

    MOCAŠ MB Enthusiast

    Messages:
    7,345
    Joined:
    Dec 27, 2008
    Location:
    West London
    Car:
    SLK
    Charles Morgan will be along soon to ask which vineyard it's from...
     
    1 person likes this.
  14. bolide

    bolide MB Enthusiast

    Messages:
    3,726
    Joined:
    Oct 8, 2005
    Location:
    Brighton
    Car:
    BMW E39 525 Diesel Touring
    He'll know which vineyard - he'll want to know which side of the vineyard...

    Nick Froome
    the independent Mercedes Estate specialists
     
    1 person likes this.
  15. RBYCC

    RBYCC MB Enthusiast

    Messages:
    1,137
    Joined:
    Aug 8, 2007
    Location:
    REHOBOTH BEACH DE USA
    Car:
    1971 280SL, 1988 300CE TT, 1994 E320 CAB, 1999 AMG C43, 2005 AMG G55K 2008 CLK63 AMG BLACK SERIES
    Typical of the M104-24V....the earlier M103-12V sounds much better on start up :thumb:
     
  16. ray_hennig

    ray_hennig Active Member

    Messages:
    614
    Joined:
    Dec 1, 2008
    Location:
    France
    Car:
    MB 300CE-24 Sportline
    Air pump, I think.

    Mine's been making that noise from when I bought it in 1997 with 135K Kms until today with 370K Kms. I think it's the air pump.

    It seems fine after 235K Kms so I'm not worrying. Maybe you shouldn't either.

    Bon courage.

    RayH
     
    1 person likes this.
  17. brigadier

    brigadier Active Member

    Messages:
    715
    Joined:
    May 30, 2010
    Location:
    London
    Car:
    500E
    Is the air pump you all are refering to is the a/c compressor?
    I had similar whine from mine, which stopped, as soon as compressor clutch disengaged. I bet on the a/c compressor.
     
  18. WDB124066

    WDB124066 MB Enthusiast

    Messages:
    6,176
    Joined:
    Apr 17, 2009
    Car:
    1996 E320 Sportline Cabriolet x 2
    Would this air pump be fitted to a 1996 non CAT E320?
     
  19. grober

    grober MB Master

    Messages:
    27,863
    Joined:
    Jun 22, 2003
    Location:
    Perth, Scotland
    Car:
    W204 C200CDI Estate
  20. DRBC43AMG

    DRBC43AMG MB Enthusiast

    Messages:
    1,079
    Joined:
    Mar 15, 2010
    Location:
    Switzerland, Sion (VS), the canton of mountains, w
    Car:
    99' C43 AMG "T Rex", 00' Renault Twingo1, Ultima Sports Can-Am
    Hmm, could someone tell me what's the purpose of the air pump?
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.