Page 1 of 2 12 LastLast
Results 1 to 25 of 48

Thread: Alternator making noise

  1. #1
    Senior Member
    Join Date
    Jan 2003
    Posts
    934

    Alternator making noise

    Does anybody know why the alternator would make a rattling noise, if not alternator mabye something around it but im sure its it!

    Elvir
    Baaa

  2. #2
    Moderator hvmercy's Avatar
    Join Date
    Dec 2003
    Location
    Northern California
    Posts
    2,019

    Re: Alternator making noise

    Originally posted by C280 JR
    Does anybody know why the alternator would make a rattling noise, if not alternator mabye something around it but im sure its it!

    Elvir
    Maybe it's one of the pulley. Or if it's the alternator then
    the bearing on it is broken.

    hvmercy

  3. #3
    Senior Member
    Join Date
    Jan 2003
    Posts
    934
    what do you mean bearing?, also the noise is making a plastic type of rattling noise.

    ELvir
    Baaa

  4. #4
    my alternator started having a grinding sound after rinsing the engine. must be a bearing
    95 C220 Moonstone/Gray mb-tex
    MODS
    - Replica Avantgarde Grill
    - Flat hood Emblem
    - Plat +4 plugs
    - In Dash Pioneer CD and pioneer speakers
    - XM Radio
    - pioneer 12\" DVC Sub
    - Boss amp
    - Blue headlights & APC signals
    - H&R Springs
    - Bilstein sports up front
    - 17\" MOMO\'s

  5. #5
    Rattling noise is often the tensioner shock. Have you had yours changed?

  6. #6
    Senior Member
    Join Date
    Jan 2003
    Posts
    934
    Originally posted by LV202
    Rattling noise is often the tensioner shock. Have you had yours changed?
    no i have not...how much does it cost

    Elvir
    Baaa

  7. #7
    The little shock is behind the water pump pulley a tad and is 20 bucks.

    The rubber gasket (at the top shock eye) gets dry and cracks. Then it's metal on metal = the clacking/rattling sound. Some people take the top bolt out and slide a rubber washer between the shock eye and mating surface. I did that first and it muffled the sound. Then it got brittle too and the sound came back.

    I put the shock in after that and it's been quiet since. The old one was worn OUT.

    The way to test is with a large screw driver, breaker bar etc. Whatever you can get down there. Locate the shock (flashlight might help), then start the car. CAREFULLY slide the scewdriver down and pry it against the shock. Try it a couple of different ways. If the noise stops...then there is the problem. It gets quiet real quick.

    Does the sound stay constant no matter what? Or just on start up?

  8. #8
    Senior Member
    Join Date
    Jan 2003
    Posts
    934
    honestly...i have not herd it these two days...i started my car two days ago, and it made nosie, i took it to the service, and it stopped when i was there..but im sure it would be back..im gonna try what you said

    Elvir
    Baaa

  9. #9
    Yea maybe it's on the way out. Be careful prying anything against it. Make sure you have some light on it when you do it.

  10. #10
    Senior Member
    Join Date
    Jan 2003
    Posts
    934
    ok i heard it again....i want to know, how big of a problem is this, is it something that needs to be done right away or can it waait

    Elvir
    Baaa

  11. #11
    Is the noise constant?

    It can wait...IF that is the problem. Did you do the test to see?

  12. #12
    Senior Member
    Join Date
    Jan 2003
    Posts
    934
    i tried some stuff but i still cannot confirm where exactly its comming from...you would not happen to have any pictures would you..

    Elvir
    Baaa

  13. #13
    Originally posted by C280 JR
    i tried some stuff but i still cannot confirm where exactly its comming from...you would not happen to have any pictures would you..

    Elvir
    Is the noise constant?

    Did you pry against the shock, or are you saying you couldn't find it?

    Is it a clanking type sound?

    When you answer the questions I'll take a pic tomorrow and post.

  14. #14
    Senior Member
    Join Date
    Jan 2003
    Posts
    934
    i just tried to pin point the location..cause i dont know where exactly it is coming from, but its coming somewhre around the alternator...right now i its slightly lighter sound i can bearly hear it next to the engine noise..but the ratling that its making is somwhat like a plastic sound even tho there is no plastic around that area...and its coming from the left side of the engine..close to the headers.(which i tought was the problem also)

    Elvir
    Baaa

  15. #15
    Sometimes the noise will travel and be in a totally different area than where it came from.

    Oil weight? What are you using? Does make a tapping noise on start up? And get better when it warms up?

    Only when it starts up? or Constant

    Tomorrow when it's cold disconnect the air pump harness (Air pump is right under the Alt. Harness can disconects at top). Then start the car. If there is no noise then you are hearing the air pump bearing going south. If you still hear noise then proceed to look elsewhere.

    You haven't answered my other questions so I can't help you any further right now. Did you pry against the shock or are you unable to find it?!?!?

  16. #16
    Senior Member
    Join Date
    Jan 2003
    Posts
    934
    i dont quite know what the shock looks like

    Elvir
    Baaa

  17. #17
    Senior Member
    Join Date
    Jan 2003
    Posts
    934
    ok....i got under the car, and the noise was coming from this black round piece of box, it looked it had a small square mesh on a side, it sat below the alternator...anybody know what this box is??

    Elvir
    Baaa

  18. #18
    Air pump is under the alt.

    Air pump bearing goes south and makes noise on start up , when it is used.

    You can disconect the air pump and start the car. If there is no noise then there is your problem.

    Follow the wiring harness from the air pump, above the alt, and behind the front (black) cover. You take the cover off, then reach back and disconect the harness.

    Start the car up and see if the sound goes away.

    Let us know the results to help future people with this problem.

  19. #19
    Senior Member
    Join Date
    Jan 2003
    Posts
    934
    there is a fat hose that connects right to it, can i take it out there? and now that i pinpointed the problem, most likely how serious is that...and what does it do..

    Elvir
    Baaa

  20. #20
    Originally posted by C280 JR
    there is a fat hose that connects right to it, can i take it out there?

    Elvir
    No.

    Once you start the car with it disconnected, THEN you have pinpointed the problem. If it is the problem, then it is most likely the bearing gone bad. In which case you will have to replace the entire pump.

    It warms up the cat on cold start.

  21. #21
    have you checked the belt tensioner? mine needs to be replaced because it makes the clicking/rattling noise everytime load is put on the engine (shift into a moving gear at idle, turn on headlights/AC..). its pretty loud also, you can hear it from the inside of the car.
    2006 WRX Limited
    1998 C280

  22. #22
    Originally posted by LV202
    The little shock is behind the water pump pulley a tad and is 20 bucks.
    are your referring to the belt tensioner? if so, where did you see it for $20? ive searched for the part and the cheapest one is around $200.
    2006 WRX Limited
    1998 C280

  23. #23
    Originally posted by ricerokets4life
    are your referring to the belt tensioner? if so, where did you see it for $20? ive searched for the part and the cheapest one is around $200.
    No, I'm talking about the belt tensioner shock. This makes a rattling sound because the bushing wears away allowing the metal to bang up against the metal.


    200 bucks is about right for the tensioner sad to say.

  24. #24
    Originally posted by LV202
    No, I'm talking about the belt tensioner shock. This makes a rattling sound because the bushing wears away allowing the metal to bang up against the metal.


    200 bucks is about right for the tensioner sad to say.
    yeh, ive been holding off on the repair cuz im getting the feeling my mechanic is ripping me off (still less than dealership though). he says ~$500 for labor to replace the entire belt tensioner assembly. i checked on various forums for some DIY instructions but to no avail.

    maybe its because of a faulty shock? how do you tell if its the shock and not the tensioner itself?
    2006 WRX Limited
    1998 C280

  25. #25
    Originally posted by ricerokets4life
    yeh, ive been holding off on the repair cuz im getting the feeling my mechanic is ripping me off (still less than dealership though). he says ~$500 for labor to replace the entire belt tensioner assembly. i checked on various forums for some DIY instructions but to no avail.

    maybe its because of a faulty shock? how do you tell if its the shock and not the tensioner itself?
    The shock is on the earlier models but not sure if it is on your year or not. Anyway, get a flash light and check down there. Mine was pretty tucked away. To see if it is the shock (once you find it, and assuming you have one) pry a breaker bar or long screwdriver against it with the car running.( Be careful while you are doing this, you don't want any accidents.) Lean on the shock and if the sound goes away that's it.

    Do a search on http://www.mercedesshop.com/shopforum/index.php3?s=

    and see if you can get an answer from a tech there. It's tough to believe the tensioner is shot at 6 yrs old.

    Keep us posted.

    Edit: 500 for labor seems pretty high to me. Unless there is something totally different about the tensioner on a V-6 compared to an I-6.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •