Airmatic noisy pump (but nothing else wrong)
11-17-2014, 10:29 AM
#1
Airmatic noisy pump (but nothing else wrong)
Since purchasing my w220 just over a year ago, I have always been aware of the pump running, ie you can hear it.
Being right hand drive the pumps location is drivers side, so I can also feel a slight vibration from the footwell (not always but sometimes)
The pump runs not long after I start the car and drive off for about 2-3 minutes
Or when an extra passenger gets in
Or when the road surface is uneven.
When I stop and park up, on closing the drivers door there is a slight air release from the system and the car drops a couple of mm.
If the car is parked up for as long as 3-4 weeks I have noted that the wheel to arch gap remains about the same over that period which seems to indicate a good seal on the system which hold up under pressure.
If I raise the car manually with the push button on the dash I get the vehicle rising info and yes it does rise.
Also there have been no airmatic diagnostic warnings ever.
This would indicate to me that all is good other than the noisy pump.
My question is do I ignore and not worry or is there something I need to check to prevent possible future failure (Also, the updated hella relay is in situ, I checked)
Very many thanks for any advice or thoughts on remedial action you guys might or might not take.
Also the prices of a new OEM pump sourced from Germany work out at around £220 sterling (not bad)
So would it be worth swapping the pump out (for peace of mind)
And is it as easy a job as it appears to be on the U tube sights (I have rebuilt engines on cars and motorbikes in the past as reference to my skill level)
Once again many thanks for any advice, and its a great car, with a great ride system, even if a bit complex.
Being right hand drive the pumps location is drivers side, so I can also feel a slight vibration from the footwell (not always but sometimes)
The pump runs not long after I start the car and drive off for about 2-3 minutes
Or when an extra passenger gets in
Or when the road surface is uneven.
When I stop and park up, on closing the drivers door there is a slight air release from the system and the car drops a couple of mm.
If the car is parked up for as long as 3-4 weeks I have noted that the wheel to arch gap remains about the same over that period which seems to indicate a good seal on the system which hold up under pressure.
If I raise the car manually with the push button on the dash I get the vehicle rising info and yes it does rise.
Also there have been no airmatic diagnostic warnings ever.
This would indicate to me that all is good other than the noisy pump.
My question is do I ignore and not worry or is there something I need to check to prevent possible future failure (Also, the updated hella relay is in situ, I checked)
Very many thanks for any advice or thoughts on remedial action you guys might or might not take.
Also the prices of a new OEM pump sourced from Germany work out at around £220 sterling (not bad)
So would it be worth swapping the pump out (for peace of mind)
And is it as easy a job as it appears to be on the U tube sights (I have rebuilt engines on cars and motorbikes in the past as reference to my skill level)
Once again many thanks for any advice, and its a great car, with a great ride system, even if a bit complex.
Last edited by baldsparky; 11-17-2014 at 10:36 AM.
11-17-2014, 11:27 AM
#2
MBWorld Fanatic!
I certainly would not be replacing the pump...
The pump mounts are pretty elaborate, with springs and rubber cushions. If the mounts are worn, damaged, or just installed improperly, there will be quite a bit of noise - you certainly should not be able to feel any vibration while the pump is running.
There are several websites with info on rebuilding the pump (replacing the piston). If you look at those sites, you will find photos and drawings that show the mount setup.
In addition - when I replaced my pump piston, I discovered that the inlet/outlet air filter was missing. After installing an inexpensive in-line fuel filter (yes, that is what the filter really is, even the factory one), the short hiss of released air when parking was much softer, and barely audible. You might see if there is a filter on your air line.
The pump mounts are pretty elaborate, with springs and rubber cushions. If the mounts are worn, damaged, or just installed improperly, there will be quite a bit of noise - you certainly should not be able to feel any vibration while the pump is running.
There are several websites with info on rebuilding the pump (replacing the piston). If you look at those sites, you will find photos and drawings that show the mount setup.
In addition - when I replaced my pump piston, I discovered that the inlet/outlet air filter was missing. After installing an inexpensive in-line fuel filter (yes, that is what the filter really is, even the factory one), the short hiss of released air when parking was much softer, and barely audible. You might see if there is a filter on your air line.
11-18-2014, 11:06 AM
#3
Thanks for the reply Wally.
Interestingly I came across this video.
The guys seems to feel he has issues because it took thirty seconds for his suspension to raise ?? Seems reasonable time scale to me.
But my reason for posting is because you can hear the pump running when the cars raising.
As said I know I have no leaks in the system but my point is my pump sounds exactly the same.
The reason I mention this is because many have said you cant hear the pump running.
Does your pump sound like this ?
Would love to know.
Interestingly I came across this video.
The guys seems to feel he has issues because it took thirty seconds for his suspension to raise ?? Seems reasonable time scale to me.
But my reason for posting is because you can hear the pump running when the cars raising.
As said I know I have no leaks in the system but my point is my pump sounds exactly the same.
The reason I mention this is because many have said you cant hear the pump running.
Does your pump sound like this ?
Would love to know.
11-18-2014, 01:20 PM
#4
MBWorld Fanatic!
As far as the time required, DAS has very specific tests in how long it should take for the pump to increase the pressure a specified amount. The thirty seconds does not seem excessive to me, since the pump is having to inflate all four struts to lift the car, and it is a small compressor.
With my S430 sitting in the open (not inside a garage), windows closed, HVAC operating, stereo at low volume, you might be able to hear the pump running if you were trying hard. It certainly isn't obtrusive, and I have never felt any vibration.
Again, increased noise could be a combination of mount problems and missing filter, or could be a problem with the pump. I would check the mounts and filter before even considering replacing the compressor.
With my S430 sitting in the open (not inside a garage), windows closed, HVAC operating, stereo at low volume, you might be able to hear the pump running if you were trying hard. It certainly isn't obtrusive, and I have never felt any vibration.
Again, increased noise could be a combination of mount problems and missing filter, or could be a problem with the pump. I would check the mounts and filter before even considering replacing the compressor.
11-18-2014, 03:46 PM
#5
Thanks Wally
I will check this weekend.
Final question, with reference to the filter location, is it obvious once the pump is viewable.
Or is it located elsewhere in the air system.
I only ask because if missing and not being familiar with its location I may struggle to see where it should fit.
Many thanks once again,
I will definitely get back with my findings once I have checked the compressor out.
I will check this weekend.
Final question, with reference to the filter location, is it obvious once the pump is viewable.
Or is it located elsewhere in the air system.
I only ask because if missing and not being familiar with its location I may struggle to see where it should fit.
Many thanks once again,
I will definitely get back with my findings once I have checked the compressor out.
11-19-2014, 09:40 AM
#6
MBWorld Fanatic!
There is one small line for the outside air that enters, and for the system air that exits, the pump for the system. The line from the pump should run to a filter that is essentially a small in-line fuel filter. The filter and it's line run up into the chassis near the pump, to protect the line from ingesting water from the road, but it should still be easily visible.
http://www.benzworld.org/forums/w220...ce-filter.html
http://www.benzworld.org/forums/w220...ce-filter.html
11-19-2014, 10:22 AM
#7
Had the afternoon to myself today and weather was good so decided to see what's going on.
The problem was the rubber mounts being worn, and the springs that support the compressor being weak.
The filter Wally mentioned was there (35 on diagram)
So by replacing items 36 to 40, I no longer have a problem.
Just for reference, you can and always will be able to hear the pump when its running.
It shouldn't be obtrusive, and you definitely shouldn't feel any vibration.
But the pump is a small electrical compressor and will be audible if you know what to listen for.
That's not my opinion, but the opinion of 3 trained mechanics from the Mercedes dealership.
One of them kindly had a listen to my pump when I picked the parts up, and let me listen to another W220 that had just been serviced.
He said "I have had customers stand next to me with the airmatic rising and they have asked is the pump running ?
Some people can hear it, some obviously cant.
Its down to if you know what to listen for above the sound of the engine running and all the other whirrs and clicks that tend to be going on around the car"
I'm glad that point was cleared up for me because I have read on the forum that you shouldn't be able to hear the pump running period.
That's clearly not the case.
Also the pump will click in and out dependant on road speed loading and road condition, all perfectly normal.
As far as the time the vehicle takes to rise when the manual raise button is used.
30 seconds to even a minute is quite acceptable.
Its all down to initial ride height before the raising starts, and how efficient the pump is with reference to wear and age.
A brand new pump will or should rise quicker than a 10 year old pump, but the difference should not be excessive.
Thank you for your advice and help Wally
And I hope my input helps someone one day with a similar problem, or to clear up some of the queries that are often asked.
Great site, Thanks again.
The problem was the rubber mounts being worn, and the springs that support the compressor being weak.
The filter Wally mentioned was there (35 on diagram)
So by replacing items 36 to 40, I no longer have a problem.
Just for reference, you can and always will be able to hear the pump when its running.
It shouldn't be obtrusive, and you definitely shouldn't feel any vibration.
But the pump is a small electrical compressor and will be audible if you know what to listen for.
That's not my opinion, but the opinion of 3 trained mechanics from the Mercedes dealership.
One of them kindly had a listen to my pump when I picked the parts up, and let me listen to another W220 that had just been serviced.
He said "I have had customers stand next to me with the airmatic rising and they have asked is the pump running ?
Some people can hear it, some obviously cant.
Its down to if you know what to listen for above the sound of the engine running and all the other whirrs and clicks that tend to be going on around the car"
I'm glad that point was cleared up for me because I have read on the forum that you shouldn't be able to hear the pump running period.
That's clearly not the case.
Also the pump will click in and out dependant on road speed loading and road condition, all perfectly normal.
As far as the time the vehicle takes to rise when the manual raise button is used.
30 seconds to even a minute is quite acceptable.
Its all down to initial ride height before the raising starts, and how efficient the pump is with reference to wear and age.
A brand new pump will or should rise quicker than a 10 year old pump, but the difference should not be excessive.
Thank you for your advice and help Wally
And I hope my input helps someone one day with a similar problem, or to clear up some of the queries that are often asked.
Great site, Thanks again.
