HQQI

I guess it was just a matter of time and Mercedes dealer verified that the humming noise from the engine was coming from the ABC pump. They requested putting a new one in but I am not sure if it is the shock absorber / damper or the pump itself not the actual pump. It does not look like the bearing are making the noise when I listen to the engine from outside. The service advisor said there is a 50% chance that the damper / shock absorber might fix the issue but I am planning to purchase the part online regardless just to see if it will...

SL550 has the shock absorber / damper (Part # A0004660010) built onto the ABC pump, unlike the older SL models (older than 2006) where the damper / accumulator was on the valve. When I open the hood I think I see the ABC Pump (I am attaching pictures to verify that the bulb shaped damper behind the white label is actually the ABC Pump damper. Can someone verify?

The dealer is asking for $450 labor just to change the damper on the ABC Pump - if I have identified it correctly it does not look like it takes that much labor to change that part on the ABC pump? Has anyone had any experience with changing this part on this newer models? Does it require removing the ABC pump from the engine?

Also, I am attaching you a video of the noise I hear from inside the car - it kicks in around 20 sec. That's the other reason why I think it is not the bearing on the pump but the damper / shock absorber since the noise kicks in after a while not as soon as I start the engine (the pump starts rotating as soon as the engine kicks in though so it might eliminate the bearing noise from the pump...)

Here is the video link:
I would appreciate some comments on this. I have seen a lot of posts about the older model damper changes but have not seen anything on the newer SL damper changes with the damper on the ABC pump (not on the valve as in the older SL models...).

TwinCam

I have a 2007 SL600 with 17,000 miles and I had the exact same noise. My front right strut had a 2 year old small oil leak coming from a seal that was leaving a spot on the garage floor. I took the car to the dealer in Ft. Meyers, Florida and the service manager found the ABC oil was low and added oil in an attempt to silence the pump. The pump was still making noise and they recommended replacing the pump before it completely failed and caused more serious damage to the ABC system. I had the service department replace the pump ($1250) and also replace the leaking strut with a MB certified rebuilt unit ($1300). The car runs great and I have had no further problems. If I had changed the leaking strut earlier, I likely would not have damaged the pump. I put so few miles on the car that I thought I could get away with not replacing the strut until the leak became major, but time caught up with me. TwinCam

SPIKES

having same issue...see related post....did you get it resolved?

HQQI

Not yet - I have purchased the part (dampener on the ABC pump) and will have the dampener replaced as soon as I find some time. I hope it fixes the noise otherwise looks like I will have to pay for the whole pump - which runs close to $3,000 with labor.

Did you get to fix yours?

WHTEVO

I was told a while back that the dampner was not available separately from the pump. What part number did you get so we have it here for future reference? Thanks.

Aaron

HQQI

The pulsation dampener/shock absorber part number is A0004660010. This part is on the ABC pump for the ABC II system (which replaced 2006 or earlier models' ABC I system in which the absorber was on the valve).

The part I have purchased has the part number A0004660310, which is the same part but is probably manufactured by a different manufacturer (or for newer models they changed the serial number). It is basically the same part so if you find either of them at a better price grab it.

Also, it looks like the user Spikes (his reply is above) has fixed his issue with the noise. I have sent him a message and curious to see how he did that. I am really sick of this noise and as soon as I find time from my busy schedule I will have this dampener replaced. It takes all the fun off of driving this car. The exhaust note was subtle to begin with and now I cannot hear any exhaust note at all

If the dampener does not fix the issue I am considering trading in this car for a 2012 SLK 350 after the summer.

SPIKES

damper solved the issue...i attempted to install myself but after removing everything the rear bolt was an issue and i ran out of patience.
got it done and what a difference.....pulsator and labor was $550

HQQI

Spikes thank you so much for the update, I really appreciate it. It makes me fell more confident now because I was thinking I was going to waste ~$600 and the noise would still be there.

By the way, you have gotten a very good deal. I have bought the pulsation dampener from eBAY for $200 and MB dealers are quoting me $400 for the labor. The part itself it close to $350 I believe if you buy it from MB dealer. Did you get it fixed at an independent shop or MB dealer?

I feel the same way as you do I tried getting to the ABC pump myself but gave up because if I screw something changing the dampener I would end up paying ~$200 to tow the car to the dealer.

Also, an advice to you - find a dealer that will change the ABC system filter on the reservoir without trying to sell you an ABC system flush. The reason is that they have recently made the pore size of the filter smaller than the original factory installed ABC system filter which captured any floating substance better. This way you can ensure your ABC hydraulic fluid is substance free.

One last question for you - When you look at the video in the original posting how does it compare to the humming noise you heard? Was the humming noise always there even from 900 RPM like mine or was it only between 2K and 3K RPMs?

Thanks again! I will keep you all posted once I get to have mine replaced.

SPIKES

i bought the pulsator from mb for 350 and labor from independant was 285.
he would do it complete for 525 plus tax which included rodeo and any fluids i guess.

noise appeared all of a sudden and all the way through the rpm range...it feels like motor is connected directly to the chassis...when i took of belt and drove it the noise was gone and eliminated all other probabilties like mounts etc....
the tech. diagnosed it immediately as the pulsator as he does many of them..
funny i was also ready to sell this car and was already looking for an 09
good luck and keep us posted.

HQQI

Update on this - I have had the dampener replaced on the ABC pump last week and all the growling and knocking noises went away. What a difference it is - I wish I had the time to get this done earlier. The dealers will push you to replace the whole ABC pump system but do not get fooled.

I think a good way to understand if it is the dampener is that if the pitch of the noise is changing as you go over the speed pumps or if after you cold start the engine the noise isn't there but after a minute it kicks in it is most likely the ABC dampener.

Here is the service details:

Client states ABC pump dampener replaced - replaced ABC pulsation dampener (client supplied part) - LABOR: $426.00

Part I have purchased off of EBAY: ABC Pulsation Dampener 0004660310 for $200.00

allanediaz

Thanks for the info! Super helpful!

One of my hose broke. I can't identify which is the correct part number. Can anyone help? The hose that broke is the upper one in the picture in the link:

https://mbworld.org/forums/sl-class-...e-problem.html

Dom388

Hi All,

I have an SL500 2007 with the same issue! I have found the part. Does anyone have the Mercedes manual with details of how to change the fluid and bleed?

Also, does anyone know how to perform the Rodeo to bleed? Is there software that can be bought to control the on board computer?

allanediaz

Hey DOM388,

What is the part number for the part you found?

Thanks,

Allan

Dom388

Hi Allan, here is the part number a found in the forum. I have not bought it yet:

A0004660310

Do you have the same issue, with noisy ABC?

allanediaz

Hahaha. In my previous post, I am asking for a hose part. I thought you found it instead of the dampener one.

Allan

Stormred08550

I have an 08 41k. Bought used at 39k..... I changed out all the fluids .... Auto .. Brakes and abc filter and pentisol....since I have no records of service...

Drove great for 200 miles....I rodeo'd the suspension a bit and tah dah....get the whine above 1500 rpm.... Now my mechanic says he has heard worse on land rovers in particular...live with it! Jeez.... I am like all here ... I can't stand the whine and I cannot hear the engine growl....... I get the dreaded abc warning .... In white (not red) and NO whine with this failure.... (I think dampener failed completely) I had purchased a pulse dampner to be put on later in the autos life..... As a hunch....I take the auto to the mechanic he says I think the tandem pump is gone ($3500 total labor and parts... And this is a master mechanic 42 years) as it was use to dirty pentisol and has now fouled somehow or viscosity is not what it was use to as my fluid was light tan.... On a fluke he takes out the pump and says wtf let's put on the new pulse dampner $379 from Miami since you have it here..... Starts diagnostics and resets laterals and guess what kids..... No whine no issues I drove the car at high speed ...+100 to my beach area and then back 100+.... No ISSUES....nada....

MEN... WOMEN.... LOOK HERE..... The issue almost always is the same. ....a small part but solves most all issues

1. The dampener and when it starts to go bad as it accepts back pressures over 200 bar pressure as rebound on the suspension.... It whines!!! Replace it for $800 parts and labor.... And you will still love your MB. Now here is my follow on thought

2. At 36k miles or 3 years more.... Replace the mineral oil fluids and the filter as the german repair place recommends as they service nothing but abc suspensions and

Yes I think you can go 200k easily on the suspension

I have zero issues with my storm red baby

asfast

.

asfast

I replace the filter and pentosin 11 and also replace the Pulsation Dampner (260$ from the dealer) in May of this year and the noise is still there.., It was a PITA to change it., I cut down a 27mm wrench to get it off and the bumper has to come off. The original was probably fine and still had the white plastic part at the top. I took it by a local euro shop and he said I can drive it with the pump noise and it won't cause a problem ., Im probably running on borrowed time. Local shop quoted 600 to change the pump.

2009 SL550

gmhohmann

Just look on YouTube. There are several good ones. Don't buy the AGA tool! Disconnect the return hose to the reservoir and bleed the old fluid into a bucket.
the Youtube video has more details.

paste

I just changed my pulsation damper, although mine was underneath the car. The pump was only changed about a year ago but the noise is still present. I'll have the belts off tomorrow as I am awaiting the final replacement pulley to install so when I have all the belts off I can verify that is in fact the pump that is making the noise and that it is not coming from the engine. There is no way to buy the tandem pumps new anymore, at least not for the W220 and there is no leaks coming from the pump on my car.