W216 CL500 Groaning noise LH side

Will Barber

Senior Member
Joined
Jan 25, 2010
Messages
234
Reaction score
60
Location
Cheshire
Your Mercedes
2012 CL500 (4.7L M278)
Hi all.

On route to an event this morning I "opened the taps" on my 2011 CL500 and immediately started to hear a whining noise. At first I thought it was the turbos but then thought it's never done that before so why should they now?
It was only briefly that I held it at full chat (10 seconds or so) and after coming off the throttle the noise disappeared after a few seconds. However on the way home, again after giving it some work to do, the noise returned but got much louder and seemed to turn into a groaning noise, coming and going for the next 30 miles or so.
Performance isn't effected, and it seems to be coming from the mid LH underside of the car.
My first thoughts are could it be the fuel pump (if it is indded underfloor mounted), or is the pump in the fuel tank on this 2012 model year car?
The car has done 67k miles and has full dealer service history.
There are no logged faults either.

Any guidance would be much appreciated.

Thanks, Will
 

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
Interesting
I think the fuel pump is under the back seats but not 100% sure on your model (plenty CL owners on here can pipe up hopefully)
I had a similar groaning on my SL which presaged my ABC pump failure
I’d get it on Star quickly to diagnose accurately- have you got an Indy you use? Plenty our way
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Check your ABC fluid level. If it's low it may be related and an ABC sphere may have failed. The pulsation damper sphere can set up some noises when it fails.
 

Craiglxviii

Senior Member
Joined
Sep 6, 2015
Messages
17,781
Reaction score
7,426
Location
Cambs UK
Your Mercedes
970 Panamera Turbo; W221 S500L AMG Line, C215 CL500, W251 R350L AMG Line, plus several more now gone
With the others, it sounds ABC-ey. The pump is that way, I seem to recall the fuel pump is integrated into the tank.
 
OP
Will Barber

Will Barber

Senior Member
Joined
Jan 25, 2010
Messages
234
Reaction score
60
Location
Cheshire
Your Mercedes
2012 CL500 (4.7L M278)
  • Thread Starter
  • Thread starter
  • #5
Okay thank you guys, will report back.
 

Flyinspanner

Senior Member
Joined
Aug 8, 2010
Messages
3,283
Reaction score
1,577
Location
Ruislip
Your Mercedes
CLK320-A209 (sold CL500 & W168)
Rear ABC sphere may have gone. -but near impossible to diagnose remotely (though it sounds like when my pulsation damper went- sphere, if so worth a flush, new filter, and refill)

Did you get any dash warning pop up, even if only transitory?

Look at your fluid, is it clear green?
Is the level correct?
Has ABC fluid ever been changed?
Does the ride seem at all more wallowy/ pitchy?
 

shine

Senior Member
Joined
Nov 2, 2010
Messages
843
Reaction score
62
Location
Hampshire
Your Mercedes
CL 500.W216 + C300 Coupe AMG Line 2018
New pulsation damper fitted on my W216 and the groaning/whining sound now gone.
 
OP
Will Barber

Will Barber

Senior Member
Joined
Jan 25, 2010
Messages
234
Reaction score
60
Location
Cheshire
Your Mercedes
2012 CL500 (4.7L M278)
  • Thread Starter
  • Thread starter
  • #8
Guys. By the looks of it, the front accumulator (A2213270215, item 125) seems to be the main item being the main filter for the hydraulic system.

The one for the rear (A2213280015, item 140) is more just a reservoir (swirl chamber) and it's the front one that does the main filtering.

I can get one for just shy of £160 so I'll give that a go and replenish the system with new hydraulic fluid. Very easy to do if it's anything like my old W215 CL... Simply lift the vehicle using a 2-post ramp (all four wheels hanging), remove the damper, fill new damper with fluid, fit the damper then bleed the system.
To bleed I simply add a long flexible hose the the reservoir return hose and stick it in a bucket, then run the engine allowing the old fluid to be dumped in the bucket whilst topping up the reservoir with fresh Pentosin until what comes out of the return hose is clean. I then repeat the process with the car on the ground whilst raising and lowing the ride heights.
I have many litres of Pentosin CHF11S in stock too!

Regards Will

CL Hyrdo.png
 
Last edited:

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
As I’ve said before Will, no expert on the CL (or anything too much !), but on the 230 (SL) which is pretty similar if I’m correct, the pulsation damper is seperate/small additional sphere. This is the schematic for the SL
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Correct John. There are 4 spheres. One per axle, one between pump and valve blocks (this is the one that usually caused noise) and one in the return to the pump.
 

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
Correct John. There are 4 spheres. One per axle, one between pump and valve blocks (this is the one that usually caused noise) and one in the return to the pump.
Yip, it was this I had been ‘hoping’ for (blind hope as it happened ) when it was in fact my pump giving up. Never mind, all in the past....:p
 
OP
Will Barber

Will Barber

Senior Member
Joined
Jan 25, 2010
Messages
234
Reaction score
60
Location
Cheshire
Your Mercedes
2012 CL500 (4.7L M278)
  • Thread Starter
  • Thread starter
  • #13
Okay thanks guys, just got the number in case anyone else requires one:

Pulsation damper: 0004660400
Cost £150 inc. vat
 
Last edited:

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
Yip don’t go buying it yet though until you’ve had the diagnostic....
 
OP
Will Barber

Will Barber

Senior Member
Joined
Jan 25, 2010
Messages
234
Reaction score
60
Location
Cheshire
Your Mercedes
2012 CL500 (4.7L M278)
  • Thread Starter
  • Thread starter
  • #15
Done the diagnostics already, nothing comes up. However, after being reminded by you knowledgeable guys, the scenario is exactly the same as it was for my old W215 CL500, so I'm 99.9% sure this will cure the problem. Even if it doesn't, at least I know this has been replaced!
Regards Will
 

Flyinspanner

Senior Member
Joined
Aug 8, 2010
Messages
3,283
Reaction score
1,577
Location
Ruislip
Your Mercedes
CLK320-A209 (sold CL500 & W168)
The sphere is like a two part ball, with a diaphragm across the centre.
During manufacture, the ‘blind’ end is given some nominal pressure and the pentosin fluid in your system then acts on the other side of the diaphragm. (This allows the system to cope with pressure changes in the pipes as the dampers move up and down - if not the pipes could simply burst, or seals blow)

The spheres are not filters. Filter is on the reservoir.
Same system below.

https://www.benzworld.org/forums/r230-sl-class/1899049-abc-fluid-filter-change-diy.html
 
Last edited:

Flyinspanner

Senior Member
Joined
Aug 8, 2010
Messages
3,283
Reaction score
1,577
Location
Ruislip
Your Mercedes
CLK320-A209 (sold CL500 & W168)
I know that MB upgraded the filter from 10micron to 3micron around 2008/9, but wonder if anyone has added anything like this aftermarket inline filter?

http://www.brrperformance.com/blog/?p=3777

What do the those of you with lots of experience think?
Worth it for boots and braces approach?
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,328
Reaction score
21,575
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
The sphere is like a two part ball, with a diaphragm across the centre.
During manufacture, the ‘blind’ end is given some nominal pressure and the pentosin fluid in your system then acts on the other side of the diaphragm.
This why the level drops when the diaphragm fails - the extra volume that was gas behind the diaphragm is replaced by fluid that can only come from the reservoir.
 
OP
Will Barber

Will Barber

Senior Member
Joined
Jan 25, 2010
Messages
234
Reaction score
60
Location
Cheshire
Your Mercedes
2012 CL500 (4.7L M278)
  • Thread Starter
  • Thread starter
  • #19
Guys. I've just been on the phone to the main dealer and they say there is no filter listed for the reservoir on this model (2012 W216 CL500) o_O
I find that a bit odd..... Can anyone shed any light on this, and maybe have a part number?
The filter A0031846101 as fitted to the W215 is not listed for fitment to my later W216. Surely there must be something there to change.
Thanks, Will
 

John Laidlaw

Senior Member
Joined
Nov 15, 2013
Messages
26,373
Reaction score
9,163
Location
Wirral
Your Mercedes
Land Rover Discovery 4
Find that hard to believe ? Wouldn’t have a magnetic filter would it by any chance?
The normal filters were changed/upgraded to 3 micron at some point
 

d:class automotive are specialists in automotive interiors and upholstery. From Mercedes and modern cars to custom and classics. Tel: 01483 722923 Email:info@dclass.co.ukWeb:www.dclass.co.uk
Top Bottom