baldsparky

There have been numerous posts regarding the airmatic suspension systems on our cars.
Many people seem to question the operation of there systems, and exactly what is right and what is wrong with that operation.
For example,
Can you hear the pump running when the systems being pressurised ?
Yes you can, its a compressor !!
However there have been comments stating its almost impossible to hear the pump.
If you press the raise suspension button and get the vehicle rising display you will hear the pump.
Its a shame there's no guide to say exactly what you can expect from this set up in normal day to day use.
ie average wheel arch to wheel heights after a couple of days standing or after a run.
How often the pump kicks in whilst driving, and what causes the pump to run on different road surfaces. ect ect.
Might be useful to have feedback on this.
I'm off to work now but intend to put my finding up later as a kick off for comparison.
Cheers guys.

wallyp

I have owned my 2003 S430 since December 2012, and could always hear the pump run, and could always hear the hiss of pressure release when parking the car.


I gradually developed problems with the system, and just a couple of weeks ago finally replaced the piston ring on the compressor. At that time I discovered that my system had no inlet air filter on the compressor - no hose, no filter, no bracket, nothing. I installed a fuel filter of the proper size, using about 10" of hose between the compressor tubing and the filter, plus a 4" piece of hose on the other end of the filter.


I can no longer hear the compressor run, nor do I hear any pressure release. I could not now locate the compressor by listening to it...


My suggestion is, if you can hear your compressor, make sure that you have an inlet filter installed.

Quadcammer

there is a filter in the parts diagram...I've seen it myself. Odd that you didn't have one.

lganski

Thats interesting because I could never hear the compressor run but could hear it purging air. The compressor was replaced once (by an MB Shop) due to a bad relay and I did not notice any change. I could not hear it even when it was running all the time.

baldsparky

I have listened to an S430 and S500 along with my own S320. When you press the airmatic raise button on the dash You get the Airmatic Vehicle Rising displayed and on all three vehicles you could hear the compressor running. Its not loud, but if you pop the bonnet and listen its there.
Once you know the sound, you can identify it should the compressor kick in on a quite stretch of road.
None of the three vehicles have any apparent issues my own included.
But I did wonder when I read on this sight that the pumps are completely silent.
Having listened to three vehicles I decided to pop into my mercedes dealer and ask the question.
They said if your listening for it, you can hear it. Its not loud, and normal road noise will probably drown it out. They also said that when travelling I may have a better chance of hearing the pump due to the fact my windows are double skinned. It cuts down on road noise so gives a better chance of hearing the pump.
Don't get me wrong its by no means loud, but a muffled whirring hum can just about be heard until the system pressurises and shuts down.

fxdeebee

'06 S 500 w/75K miles


Have never heard anything except the purge after shut down, and even then only in my garage. If it can be heard it too low a level for me. ( I do have significant hearing loss from years around Navy flight lines ) I THINK I hear it in the garage when I raise the car with the button, but not enough to bet my own money on it. Have not tried putting the Spousal Unit in the car and have her manipulate it while I stand outside though.

mcguirja

I can hear my car regularly purge air, but don't hear the compressor run. I've never had issues with the system, however, last summer when I was using my SL as daily driver, the "S Class" did rise up from its normal height from sitting for long periods. Starting it and taking it for short drives brought it back to normal height. I started driving it again regularly in the late fall and it has been operating normally.

tusabes

SL has a hydraulic suspension (abc) and does not use airmatic

mcguirja

The S Class suspension rose up when it wasn't being used regularly as I was driving the SL daily. Sorry for the confusion