I do not believe there are symptoms of bad pulse dampeners (just downstream of ABC pump). The bad dampener on my car had no symptoms at all.
Accumulators on the valve blocks throw errors like "visit workshop" or a rough ride.

 

Two signs of pulsation dampener (the one mounted on the backside of the ABC pump) failure ... :

1. An alert appeared in white print--as opposed to red--on the instrument cluster: ABC FAILURE. VISIT WORKSHOP ... or words substantially to that effect. The alert disappeared after fewer than 5 minutes and never appeared again.

2. Simultaneously with the alert, a noise emerged from the engine compartment. My first thought: this sounds like an idler pulley bearings failure, or maybe some other pulley bearings failure. But upon raising the hood and using a length of rubber hose as a rudimentary stethoscope, it was quickly obvious that the sound came directly from the dampener.

I never noticed that my car rode any differently before or after the dampener failure, or even after the dampener was replaced with a new unit, but it sure is a lot quieter.

Does this help any?

 

Should also mention that some owners of the dampener mounted in the wheel well (not on the pump) experience a 'humming noise' from 1500-2500 RPM. Mine did not do this.

 

There were no physical problems - i.e. height issues or messages on the dash on my 2007 SL550 but, like Heatwave, I went looking for bearing problems due to the noise and found none. Again the noise was most apparent between 1500 and 2500 rpm.

I changed the pulsation damper and all is quiet again. Easy fix.

 

For anyone thats had a pulsation damper problem, did anyone notice any extra vibration appear in the steering wheel ? Or is it just mainly a noise from the engine bay ?

 

It's hard to say. I first noticed the noise. I was on the freeway and had been in moderate traffic, and I assumed the sound was coming from a noisy gearbox or differential on a nearby dump truck. After I got out of traffic and was on the open road and still heard the noise, I knew something was wrong. I might say I felt some more vibration in the steering, but I'm not sure. My previous car was a CLK550, so same engine and transmission. The first thing I noticed about the SL550 was some more "engine feel" in the steering column. So maybe that was the beginning of the pulsation dampener failing, or maybe it's just normal for the SL with the ABC pump near the steering column. Now, I don't notice it, so like I said, it's hard to say!

 

That’s interesting, so the noise you had was quite obvious by the sounds of it , ie not a subtle symptom. You mention the engine feel through the steering wheel, this is the thing I have and find it surprising for this level of car and not a good thing at all. On the U.K. cars the abc pump is on the opposite side To the steering wheel and I still feel it, so maybe it is designed in/ normal on these cars ? Or as you say, maybe it’s the first sign of a damper failure.

 

My ‘08 had a noticeable noise at idle or speed, at first I thought it was the brake system which pressurizes at wake up. But after a lot of diagnosis swapped the dampener, the first one was bad second works fine. I had a few other repairs happen around this same time that clouded the dampener issue, but everything led back to that part.

 

was the first damper replacement faulty from new ?

or I noticed there are actually two parts called a damper. One is the nitrogen sphere, and the other is a cylindrical tube that’s attached to the abc pump via banjo bolts.

most people seem to mention the sphere, so I don’t know how the cylinder damper differs in function.

 

The first dampener was in a box with no seal, visibly repainted and refurbished, returned without installing. As you know the guts are inside and if there is a pinhole or other defect the dampener is shot. Second item in a sealed box and bag has performed flawlessly for 2+ years. The dampener is the spherical item in my ‘08 on top of pump

 

BTW my biggest symptom was the noise, second a slight vibration steering wheel, very slight.

 

Folks, I have just preferred a brand new pulsation dampener from mercedes. On receiving it , I just shook the dampener & felt there is something v like a ball inside which is free to move.
The old dampener that came out of the car has nothing like that,

Is my new dampener part damaged?

Thanks in advance.

 

Dido
It isn’t new, even from Mercedes they rebuild them. I didn’t have any rattling in mine…that can’t be right


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Agreed no rattle in mine. My symptoms were vibration in steering wheel and foot well. 2007 dampener on pump. Ez diy.

 

How did you figure out it was the dampener and not the pump itself?

 

It's a good question. On my car the symptom was a buzz felt in the steering wheel mostly with a whirring sound just above idle up to about 2000 or 2500 RPM. On a bad pump, in my automotive experience, the noise will almost always get louder and not go away when the engine reaches 2000 or 2500 RPMs. The pulsation buzz must be a dynamic occurring only in that rev range.

 

can you please tell me it was which damper? The one mounted to the pump or the other one

 

When these parts are bought from FCPeuro, they're guaranteed for life so when they wear out you don't have to buy them again. Although they're probably good for at least ten years after install. When replacing accumulators, just replace all of them at once, and also replace the pulsation dampener at the same time, that's what I did. This way they're all new and you'll probably never have to think about them again. I haven't replaced any parts yet under FCPeuro's lifetime warranty, but I would imagine that one would have to send them the worn out parts first in order to get new ones, meaning the car would sit a bit taken apart. Good to have a spare car. Many R230 owners have more than one car, so waiting for a few days or a week, isn't really a problem. I was unaware the car has two pulsation dampeners?