Alternator making noise

[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

[hvmercy]

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

[C280 JR]

what do you mean bearing?, also the noise is making a plastic type of rattling noise.

ELvir

[fastmayte]

my alternator started having a grinding sound after rinsing the engine. must be a bearing

[LV202]

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

[C280 JR]

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

[LV202]

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?

[C280 JR]

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

[LV202]

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.

[C280 JR]

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

[LV202]

Is the noise constant?

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

[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

[LV202]

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.

[C280 JR]

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

[LV202]

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?!?!?

[C280 JR]

i dont quite know what the shock looks like

Elvir

[C280 JR]

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

[LV202]

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.

[C280 JR]

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

[LV202]

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.

[ricerokets4life]

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.

[ricerokets4life]

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.

[LV202]

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.

[ricerokets4life]

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?

[LV202]

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.

[C280 JR]

ok so what you are telling me is that i need to get an air pump bearing, and not the black box also..btw, how much is that, and can i do it by my self...if you know the price..thanks

Elvir

[LV202]

Originally posted by C280 JR
ok so what you are telling me is that i need to get an air pump bearing, and not the black box also..btw, how much is that, and can i do it by my self...if you know the price..thanks

Elvir

You have to first isolate the nosie to know what it is.

The bearing, is not sold seperately. You have to buy the entire air pump. If that is what it is.

If it is the pump...it is a DIY project. If you are that kind of guy. Are you?

[C280 JR]

i guess i can do it my self, i always tend to have people around on my first new thing that i work on,...but how much is the air pump, cause its really getting anoying having to hear the rattle..

Elvir

[LV202]

Originally posted by C280 JR
i guess i can do it my self, i always tend to have people around on my first new thing that i work on,...but how much is the air pump, cause its really getting anoying having to hear the rattle..

Elvir

Does the rattle go away after warm up? Say 2- 4minutes? If it keeps rattling it's not the air pump.

New pump is 300 bucks online.

[C280 JR]

it keeps rattling, non stop, like i said, when i looked under the car, it made noise from the black box...so i dont know what is the process that i need to do to replace that

Elvir

[LV202]

Originally posted by C280 JR
it keeps rattling, non stop, like i said, when i looked under the car, it made noise from the black box...so i dont know what is the process that i need to do to replace that

Elvir

I doubt it is the air pump then.

Probably the tensioner shock.

Take it to a tech.

[moedigga]

Elvir I just had to replace my alternator cause the bearing was done. So much for german precision bearings. Anyway your description of sound and location is similiar to mine. I do have 43 though so may be in diff location. Cost for me with dealer cost on parts was 900.00 total, totally suuuuuuuuuucks.

[LV202]

Originally posted by moedigga
Elvir I just had to replace my alternator cause the bearing was done. So much for german precision bearings. Anyway your description of sound and location is similiar to mine. I do have 43 though so may be in diff location. Cost for me with dealer cost on parts was 900.00 total, totally suuuuuuuuuucks.


900 bucks!!!??? Are you sh*ttin' me?

Man...find an Indy, unless you have a lot of money you like to throw around.....:eek:

I was thinking it may be a pulley bearing too. There is one, directly to the right of the Alt. also.

Best bet is find an Indy and take it to him. See what he says. I doubt it's a big deal.

[moedigga]

Actually lookin at receipt now 627 for alternator and 224 labor. 851 total. Dealership is lot o money. But I get Vip treatment cause its my bestfriends family dealership. And hes got a few years and family members to go before he can really give me the hook.;)

[LV202]

List price for Alt on Fastlane for AMG is 330 bucks. It's usually two bolts and maybe 15 minutes to replace. Glad I'm a DIY.

How do you like Columbia? I have been thinking about moving to Charlotte NC.

[moedigga]

Columbia is alright. Its an up an coming college town. Been here about 7 years now. From Mass but went to college here at USC and I'm still here.

[C280 JR]

looks like im gonna sell the car tomorow, so if it is the same problem 900 bucks is gonna be spent by some other person..hopefully it goes well

Elvir

[C280 JR]

i went to my mechanic, he siad it cost somewhere around $600 for the part if its fixed, and $800 for a new one..plus labor..he said its somehting like air pump or somehting, inside that black box, but i forgot what its called WHAT IS THE BOXES NAME?...he said the whole box needs to be removed for a new one..

Elvir

[LV202]

You can buy the air pump for 300 bucks online.

[C280 JR]

where...that is a pritty god deal..comapred to the stealership

Elvir

[LV202]

http://www.mercedesshop.com/catalog/index.php3

[C280 JR]

thanks...i did not know they had it...hope it wont give out on me during my trip to florida...

elvir

[LV202]

Dude if it is the air pump it only comes on for a minute or so during a cold start. It is not something that will leave you stranded. You *may* fail emissions later down the road, but you won't be by the side of the road.

[C280 JR]

what is the process of replacing an alternator...i already replaced a voltage regulator on the car when it died, but it did not do any good, so i have to change the alternator. On other cars i noticed around one scew it can be adjusted so it can tighten the belt, but on the benz i have not noticed that, all i see is two screws..do i just take those two scres out in order to take out the alternator, or is there more to it than that? and if so what is the process after you put it back into place to tighten it?

Elvir

[LV202]

You have to release the tension on the belt first. On mine you have to unlock the allenbolt (8mm I think) on the front of the tensioner. It is tucked away near the front, feel for it. Then there is a vertical bolt (it is hollow) behind it. Loosen that a turn or two and belt should loosen up. There is a pointer there too (on top), to show you your tension. Look at what it is before you untighten anything. If you can't find the allenbolt hole, use the vertical bolt as a start point. Then look forward. The allenbolt hole is facing the radiator. Get a light and shine it down there to find all this.

Do NOT over tighten it when you put it back on. If it is the same tensioner unit as mine, it is prone to break easily. I.E. keep an eye on the pointer.

Pretty easy once you get going.

[C280 JR]

where are the allenbolt and the vertical bolt located at, if you could post a picture if you have one?

or can this help...

http://img.eautopartscatalog.com/live/F400068244BOS.JPG

Elvir

[LV202]

Allen bolt and vertical bolt are part of the TENSIONER assembly. Not the alt. You have to loosen the tension on the belt before you can take the alt off. On my car (1994) the tensioner is on the (facing the car) right side of the pulleys. I had a pic to help another guy, but it got deleted. My digital isn't working right now either.

Pay attention to the directions if you decide to loosen the tensioner. Again, like I said, it is prone to easily break if you over tighten it. Just use common sense. I won't be back online for another 2 weeks or so. So good luck.

Keep us posted.

What ever happened with the air pump? BTW if it is not belt driven it is ok to let it go. No big deal. But if it is belt driven you have to address it.

[C280 JR]

thanks alot, the air pump still makes the noise..ive been through hell and back with my vacation, where my car broke down, so i really did not have time to focus on that part as it still works in a way...my main concern is the atlernator now...thanks again

Elvir