Cl216 08 5.5 buzzing when accelerating

[Bodo]

Hi,
I am happy owner of CL216 from 2008. I had 2 issues with her, 1 with batteries which is solved now and 1 more.
Car works smoothly, engine runs great, gearbox, suspension, airmatic takes it up and down easily, it doesnt drop. However I noticed when I press gas pedal it makes a bit of buzzing noise and it can be heard when driving slowly in local roads. On a motorway I cant hear it so it either doesnt buzz or I simply cannot hear it. It doesnt sound like noise from used bearing but more like buzzing. Belts, pulleys, oil for power steering are all ok. I came across information it can be airmatic pump and the advice was to replace relay with filter. Has any of you encountered something like this? I will be grateful for any suggestions.

 

[brandwooddixon]

Its always wise to get the ABC (hydraulic not airmatic) checked over. On the previous model there was an issue whereby the pulsation dampener would fail and this would cause a sort of low pitched hum.
The pump can generate a similar noise if it is worn or if the fluid level is low.
If the issue is caused by either of these then I'd expect it to be more prevalent when raising the vehicle. Raise and lower the car several times to check, generally its heard more from within the vehicle than without.

You can check the oil level yourself - the dipstick has two marks - one for when the engine is running, one for when its not. The oil should be a light green colour. If its black or the level isn't between the two marks when you check it then there are issues. If the level with engine off is okay, but very low when the engine is running then you'll have a failed accumulator in the system.

After that your best bet is to get it checked over by a specialist.
STAR diagnostic can give a full readout of system pressures to indicate a worn pump, which includes pressure spikes that may be caused by worn/failed accumulators and pulsation dampener.

Putting the car on a lift and having the engine running also gives the opportunity to more easily locate where the noise may be coming from.

I'd recommend getting the ABC system serviced regularly, say every 40k miles - its not cheap, mostly due to the cost of the oil and the amount needed to flush the system, but its cheaper than getting a new pump.

 

[Bodo]

I don’t have ABC, I have an air one Airmatic and works as it should, up and down, stays up all the time.

 

[brandwooddixon]

Okay. I didn't realise that they actually made a W216 with Airmatic. I know that they fitted it to the S-class, but as far as I was aware ABC was standard fitment for all CL class 215s and 216s. My mistake.

 

[Submariner1]

Okay. I didn't realise that they actually made a W216 with Airmatic. I know that they fitted it to the S-class, but as far as I was aware ABC was standard fitment for all CL class 215s and 216s. My mistake.

I have a 2009 CL500 ( with the model year change 2009 code)
I had that buzzing noise when just accelerating from tickover onward than disappeared. Garage said it was a pulley.
Luckily the best Mechanic I know just looked at it and said Pulsation damper!
A real bugger to fix as the pump has to come off! £££££

I took it to MBS Southampton. They know how to get at this very economically. All sorted!
To my knowledge all CL500s W216 were ABC.
I did read about a DIY conversion to airmatic?

 

[Submariner1]

I don’t have ABC, I have an air one Airmatic and works as it should, up and down, stays up all the time.

Do you have one of these?
your problem description was identical to mine …. Sorted with a pump pulsation damper.
Does yours look like mine:


Except mine is definitely ABC … green fluid
If you are Positive it has Airmatic, then maybe they have some equivalent damper after the airpump?

 

[Bodo]

Hi again,
Sorry I haven't checked properly, I thought that I don’t have ABC because I don’t have abc button on the dashboard. Just checked under the bonnet and I have an active body control and pulsation dumper. ABC oil level is good and light green colour.
I read a lot about it and I am 99% sure it is a pulsation dumper problem.
Can you recommend any garage in Surrey to fix this problem?
Or is there an easy mechanical fix just unscrew old one and screw new one, of course keeping everything really clean.
Do I need to re code anything?
Where I can get one from? I just saw one reconditioned on EBay and shipping from Europe, should I check with main dealer?

 

[Blobcat]

Hi again,
Sorry I haven't checked properly, I thought that I don’t have ABC because I don’t have abc button on the dashboard. Just checked under the bonnet and I have an active body control and pulsation dumper. ABC oil level is good and light green colour.
I read a lot about it and I am 99% sure it is a pulsation dumper problem.
Can you recommend any garage in Surrey to fix this problem?
Or is there an easy mechanical fix just unscrew old one and screw new one, of course keeping everything really clean.
Do I need to re code anything?
Where I can get one from? I just saw one reconditioned on EBay and shipping from Europe, should I check with main dealer?

I’d be heading a little bit south to @alexanderfoti

 

[bembo449]

There is a sport button pal , im sure my 216 has one but its not on the dash like in the 215

 

[Submariner1]

There is a sport button pal , im sure my 216 has one but its not on the dash like in the 215

There is No ABC button, there is a Raise Car button, and you can choose your drive mode e.g. Sports mode.

 

[Submariner1]

Hi again,
Sorry I haven't checked properly, I thought that I don’t have ABC because I don’t have abc button on the dashboard. Just checked under the bonnet and I have an active body control and pulsation dumper. ABC oil level is good and light green colour.
I read a lot about it and I am 99% sure it is a pulsation dumper problem.
Can you recommend any garage in Surrey to fix this problem?
Or is there an easy mechanical fix just unscrew old one and screw new one, of course keeping everything really clean.
Do I need to re code anything?
Where I can get one from? I just saw one reconditioned on EBay and shipping from Europe, should I check with main dealer?

I strongly recommend MBS. There used to be a poster on this site called Malcolm, aka Television, he kindly spoke to me and gave me their details - he said they were the best at ABC he knew!
Apart from being a true gentleman, boy did he know his stuff. ( ask around). very sadly he passed away.

MBS really understand ABC especially on CLs (e.g. my car is main dealer serviced, but they never looked at the ABC level arms, MBS spotted they were nearly seized up - big nasty if they do, and they were not even servicing the car!) ; they also have a unique filler tool to change the ABC oil ( I know I imported it from the States - and they were so impressed they bought it off me). They also know all the oddities, like on my car, if you undo the ABC filter it dumps all the filtered crap straight into the pump input. They know how to get around this etc.

In this Pulsation Damper case; they know the little trick, so they can get the Damper off, and replace it by just loosening the ABC pump. Huge saving in cost, no dismantling the pulleys etc.
No it will not just unscrew, well it will actually partially unscrew, but just far enough to cause a leak and let any crap there get into the pump. They clean it up perfectly so that does not happen.

I drive from North of Maidenhead to them for ABC issues, I inherited another house in Ripley Surrey, so I know from Surrey its half the distance.

Re the damper ABSOLUTELY BUY NEW FROM A MAIN DEALER - Grangemouth do great discounts £50 ish. Its a cheap Part!
I was quoted £650 labour from a main dealer!
If you use a second hand damper imo its the equivalent of buying a second hand oil filter! It will be just a matter of time before you are replacing it Again. Plus if it came off a ‘dirty ABC oil’ Car , you could be injecting more dirt than you have in your entire system.

MBS are also exceptionally good £ value.
But Hey its your choice.

Get it sorted quickly, mine deteriorated from almost imperceptable, to not a pleasant sound in about 200 miles. That hammering noise aint good for valves and the other dampers! Think 200 psi jack hammer.

 

[bembo449]

There is No ABC button, there is a Raise Car button, and you can choose your drive mode e.g. Sports mode.

Thars the same thing sub

 

[brandwooddixon]

With the system running at around 3000psi (200 atmospheres) it doesn't take much of a leak to cause trouble.
With these parts, I'd agree with purchasing from MB and new. They may even qualify for the two year guarantee on parts.

 

[Bodo]

Reconditioned parts cost almost the same money as genuine one, waste of time using the rebuilt ones

 

[Bodo]

Problem sorted.
Pulsation dampener replaced, that was the issue.
Thanks for your help

 

[bembo449]

Result and thanks for updating the thread

 

[Bodo]

New one