SL/R230: Pulsation Damper
Thread Starter
Newbie
Joined: Dec 2024
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2008 Mercedes SL550
Pulsation Damper
I've got a 2008 SL550 that makes a whining, almost "roaring" sound when accelerating through the lower gear rpm's. When it gets to higher speeds, it's fine. I thought it might be (either) a failing ABC tandem pump or the pulsation damper. Took it to the MB dealer who said pump was fine but engine mounts were shot. Replaced them, along with a new tranny mount as well. Helped a little, but sound is still there. The MB service manager said MB had lots of issues with that pump, and has a blanket warranty on them until 2030 ! I was told they don't like replacing the ABC Tandem Pump because it's warranty work, and the service dept. doesn't make as much markup on the work. Anyone have any thoughts? I've looked at YouTube videos of this same issue, and it sounds very similar. Could it be something else? Suggestions?
Thanks
Thanks
Super Member
Joined: Sep 2018
Posts: 746
Likes: 185
From: Melbourne, Australia
2005 SL 500 R230
In your year the damper is on the pump. The symptoms you describe are dead-on for a failed damper.
I would just replace it, but are you feeling the whine through the seats too? If so then that's more evidence of the PD, especially as you have new mounts which can give a similar feel through the seats when they're shot, albeit more of a grinding vibration.
I would just replace it, but are you feeling the whine through the seats too? If so then that's more evidence of the PD, especially as you have new mounts which can give a similar feel through the seats when they're shot, albeit more of a grinding vibration.
Thread Starter
Newbie
Joined: Dec 2024
Posts: 3
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2008 Mercedes SL550
Pulsation Damper
Thanks, Tom. Quick question....when you said the damper is "on" the pump, does that mean the whole pump needs to be replaced, ot can the damper itself be swapped out?
Also, what does PD mean? You referenced the abbreviation If I was feeling any vibration under the driver's seat, which I'm not.
Thanks again for your insights.
Steve
Also, what does PD mean? You referenced the abbreviation If I was feeling any vibration under the driver's seat, which I'm not.
Thanks again for your insights.
Steve
Super Member
Joined: Sep 2018
Posts: 746
Likes: 185
From: Melbourne, Australia
2005 SL 500 R230
I've never heard of the ABC pump being covered by a blanket warranty - was the service tech mistaking the ABC for the SBC warranty? Cheers Socks
Highly likely that's what the tech meant; from this I would infer that he knows nothing about the car, since the ABC pump is not covered by warranty, but the SBC pump is, in the USA (and possibly all of NA).
PD = Pulsation dampener (my lazy abbreviation). Yes it's replaceable but no five minute job. See this from Rodney https://www.benzworld.org/threads/pu...alced.3007605/
Don't even think about getting the dealer to do it - do it yourself or find a good independent.
HTH!
Highly likely that's what the tech meant; from this I would infer that he knows nothing about the car, since the ABC pump is not covered by warranty, but the SBC pump is, in the USA (and possibly all of NA).
PD = Pulsation dampener (my lazy abbreviation). Yes it's replaceable but no five minute job. See this from Rodney https://www.benzworld.org/threads/pu...alced.3007605/
Don't even think about getting the dealer to do it - do it yourself or find a good independent.
HTH!
Thread Starter
Newbie
Joined: Dec 2024
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2008 Mercedes SL550
Clarification!
Hi Tom & "Socks",
Need some clarification. Tom, what is this PD you referred to in your reply, and "Socks", what does SBC stand for? Never heard the abbreviations before. I'll talk with the MB service tech again, but when I told him about my ABC pump concerns, he asked for the VIN #, looked it up, and said it was warranteed till 2030. Maybe he was mistaken. I'll check with him again. Thanks.
Steve
Need some clarification. Tom, what is this PD you referred to in your reply, and "Socks", what does SBC stand for? Never heard the abbreviations before. I'll talk with the MB service tech again, but when I told him about my ABC pump concerns, he asked for the VIN #, looked it up, and said it was warranteed till 2030. Maybe he was mistaken. I'll check with him again. Thanks.
Steve
Junior Member
Joined: Aug 2020
Posts: 41
Likes: 9
2009 SL 550; 2022 GLE 450
Steve - SBC = sensotronic brake control, i.e., the electro-hydraulic brake by wire system on the SL class and a couple of others. ABC = active body control, which is the suspension system on the SL class which is the likely culprit of your problem. Cheers Socks
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Super Member
Joined: Sep 2018
Posts: 746
Likes: 185
From: Melbourne, Australia
2005 SL 500 R230
If you can get it under warranty then it's your good fortune, but I think he made a mistake. Our cars are getting old, so newer staff there may not know much about them. Chances are he confused the SBC unit with the ABC pump.
The pulsation dampener is the dome on top of your ABC tandem pump (which you referenced in your initial post) - this is most likely the cause of your issue.
The pulsation dampener is the dome on top of your ABC tandem pump (which you referenced in your initial post) - this is most likely the cause of your issue.
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Super Member
Joined: Aug 2017
Posts: 520
Likes: 203
From: Scottsdale AZ
2015 SL550 & 2012 S550 4matic
You can replace the dampener in situ by loosening the pump and moving a few items around. I bought the part from fcpeuro.com. I used the procedure found in post 9 in this thread below. I modified it slightly in that I just loosened the pump bolts enough to get access to the dampener but leaving enough of the pump tight enough to get leverage. As I stated in my post then, my dampener was seized, so be prepared.
https://mbworld.org/forums/sl-class-...r-replace.html
My symptoms were identical to yours at 27k miles and replaced mounts as you did and dampener ….quiet as new now.
You might also consider flushing your ABC system and changing the filter, not in MB maintenance plan but vital if you want to protect the parts of the suspension. Plenty of DYI solutions in this forum, no special tools required.
Keep us posted on what happens,
https://mbworld.org/forums/sl-class-...r-replace.html
My symptoms were identical to yours at 27k miles and replaced mounts as you did and dampener ….quiet as new now.
You might also consider flushing your ABC system and changing the filter, not in MB maintenance plan but vital if you want to protect the parts of the suspension. Plenty of DYI solutions in this forum, no special tools required.
Keep us posted on what happens,
