Desperate For Airmatic Pump Help Before Trip!
Thread Starter
Newbie
Joined: Dec 2015
Posts: 3
Likes: 0
2003 MB W220 S500
Desperate For Airmatic Pump Help Before Trip!
Hey Guys,
This is my first post but I have used the site to get answers to many questions in the past and for that I thank you all.
YES, I have absolutely looked EVERYWHERE for answers.
I would have jumped off a cliff before now with my issues but we don't have any cliffs in Orlando!
The whole story is long and boring so I'll try to keep it short.
2003 W220 S500 Base.
A few issues I took on myself got me to this point.
Back struts both test fine, no issues.
Both Right and Left front struts replaced, all good.
Airmatic pump, relay, filter etc. replaced, all good.
Acceleration sensors, just replaced.
Tested all over as much as I can with soapy water, doesn't appear to be any leaks.
Car is level now, no issues there. Ride height sensors replaced.
BUT..... the pump seems to be running almost constantly!! The pump seems to do its normal thing at start up and turn off. I get on the road, the pump runs, brick street, smooth roads, highway, the pump is running
I hear it stop when I come to a stop myself, I pull away, off it goes again.
I had it on the Start scan system just yesterday and was getting no errors or issues. The only one I had was the day before about the acceleration sensor, I replaced that, the error went away.
When I come out in the morning, the car is sitting just fine, yada yada.
I am supposed to take a trip to Miami tomorrow and of course I'm concerned about this GD Crazy *** Pump!!
ANY SUGGESTIONS WHATSOEVER WOULD BE GREATLY APPRECIATED.
Thank You
This is my first post but I have used the site to get answers to many questions in the past and for that I thank you all.
YES, I have absolutely looked EVERYWHERE for answers.
I would have jumped off a cliff before now with my issues but we don't have any cliffs in Orlando!
The whole story is long and boring so I'll try to keep it short.
2003 W220 S500 Base.
A few issues I took on myself got me to this point.
Back struts both test fine, no issues.
Both Right and Left front struts replaced, all good.
Airmatic pump, relay, filter etc. replaced, all good.
Acceleration sensors, just replaced.
Tested all over as much as I can with soapy water, doesn't appear to be any leaks.
Car is level now, no issues there. Ride height sensors replaced.
BUT..... the pump seems to be running almost constantly!! The pump seems to do its normal thing at start up and turn off. I get on the road, the pump runs, brick street, smooth roads, highway, the pump is running
I hear it stop when I come to a stop myself, I pull away, off it goes again.
I had it on the Start scan system just yesterday and was getting no errors or issues. The only one I had was the day before about the acceleration sensor, I replaced that, the error went away.
When I come out in the morning, the car is sitting just fine, yada yada.
I am supposed to take a trip to Miami tomorrow and of course I'm concerned about this GD Crazy *** Pump!!
ANY SUGGESTIONS WHATSOEVER WOULD BE GREATLY APPRECIATED.
Thank You
Last edited by JustMe321; Dec 20, 2015 at 01:23 PM.
MBWorld Fanatic!
Joined: Jan 2008
Posts: 6,151
Likes: 533
Mercedes
You didn't say what was wrong that caused you to replace all those airmatic parts in the first
Place . Clearly you had a problem before which you didn't describe
It is normal for the pump to come on when driving , as long as it's not on 100% of the time because that will burn out the pump
Place . Clearly you had a problem before which you didn't describe
It is normal for the pump to come on when driving , as long as it's not on 100% of the time because that will burn out the pump
Thread Starter
Newbie
Joined: Dec 2015
Posts: 3
Likes: 0
2003 MB W220 S500
Thanks.
I got the car from a friend, the front struts were torn and crappy so I changed them. I had a leveling issue so I swapped out the ride height sensors and I changed the pump when I thought it might be done. I was wrong about the pump, it was fine but yes, it pretty much runs ALL the time for no apparent reason.
I got the car from a friend, the front struts were torn and crappy so I changed them. I had a leveling issue so I swapped out the ride height sensors and I changed the pump when I thought it might be done. I was wrong about the pump, it was fine but yes, it pretty much runs ALL the time for no apparent reason.
MBWorld Fanatic!
Joined: Dec 2012
Posts: 2,474
Likes: 439
From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
I will say up front that I don't know what the problem is - but I can throw out some ideas.
Either the system is leaking or it is not.
If it is leaking, it is leaking only when the car is moving. I feel that is unlikely, based only upon the fact that I have not heard of such a leak, and can't think of a likely failure that could cause that.
One possible test would be to jack each corner of the car in turn, with the engine running. If there is a strut fault that could cause a leak when the strut extends, but stops instantly when it retracts to the normal ride height, that might catch it. You could also try using the lift button to check for leaks when the car is higher than normal.
If the system is not leaking, there must be something in the control system that is causing the pump to run, and the system is just bleeding off the excess air. I can't think of any really likely cause for that failure either.
Perhaps a ride height sensor that reads too low for a few seconds, then too high for a few seconds? Driving the car in the lifted position might be interesting. Or devising a way to move each sensor thru its range as you measure output.
Perhaps a pressure sensor that is too sensitive or erratic?
Are you certain that what you hear is the Airmatic pump? Pulling the fuse and driving the car might be interesting. If it is leaking, the car will go down. If it isn't leaking, perhaps you could put a temporary switch on the pump by pulling the fuse and making a jumper with an in-line fuse and a toggle switch that plugs into the fuse socket. That would let you make your trip without burning out the pump, but allow you to turn the pump on when necessary.
I hope that you let us know what you find...
Either the system is leaking or it is not.
If it is leaking, it is leaking only when the car is moving. I feel that is unlikely, based only upon the fact that I have not heard of such a leak, and can't think of a likely failure that could cause that.
One possible test would be to jack each corner of the car in turn, with the engine running. If there is a strut fault that could cause a leak when the strut extends, but stops instantly when it retracts to the normal ride height, that might catch it. You could also try using the lift button to check for leaks when the car is higher than normal.
If the system is not leaking, there must be something in the control system that is causing the pump to run, and the system is just bleeding off the excess air. I can't think of any really likely cause for that failure either.
Perhaps a ride height sensor that reads too low for a few seconds, then too high for a few seconds? Driving the car in the lifted position might be interesting. Or devising a way to move each sensor thru its range as you measure output.
Perhaps a pressure sensor that is too sensitive or erratic?
Are you certain that what you hear is the Airmatic pump? Pulling the fuse and driving the car might be interesting. If it is leaking, the car will go down. If it isn't leaking, perhaps you could put a temporary switch on the pump by pulling the fuse and making a jumper with an in-line fuse and a toggle switch that plugs into the fuse socket. That would let you make your trip without burning out the pump, but allow you to turn the pump on when necessary.
I hope that you let us know what you find...
Senior Member
Joined: Apr 2012
Posts: 432
Likes: 96
From: Just north of Detroit,Michigan
2012 E350 4Matic P2
Put the old relay back in as long as it was still working when you swapped it for the new one. Hard to believe that a new relay would fail so soon but it is possible. If the pump is running all the time, it would eventually over heat, trip the relay and shut off.
Are you absolutely certain that what you hear running is the airmatic pump??
Good luck,
Bob
Are you absolutely certain that what you hear running is the airmatic pump??
Good luck,
Bob
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Thread Starter
Newbie
Joined: Dec 2015
Posts: 3
Likes: 0
2003 MB W220 S500
UPDATE...... Same LOL, Look
So it's been a while but here's my update on this!
I am determined to find out what's up here and I actually ended up buying a complete MB Star Diagnostics System (lol, yes I did)
I ran all the Airmatic tests and the Star system tells me that everything in that area is working and running perfectly
I was really hoping I'd find an error and/or leak but nope, all is well......
SO..... What the hell can it be now?
To recap, I drive the car, the pump comes on and pretty much stays on. I come to a stop or light, it spits out a little air and stops. I pull away, it comes on! I drive at 30 locally, it's on, I drive at 100, it's on.....
If anyone on the planet has ANY ideas, I'd LOVE to hear them
Thanks
I am determined to find out what's up here and I actually ended up buying a complete MB Star Diagnostics System (lol, yes I did)
I ran all the Airmatic tests and the Star system tells me that everything in that area is working and running perfectly
I was really hoping I'd find an error and/or leak but nope, all is well......SO..... What the hell can it be now?
To recap, I drive the car, the pump comes on and pretty much stays on. I come to a stop or light, it spits out a little air and stops. I pull away, it comes on! I drive at 30 locally, it's on, I drive at 100, it's on.....
If anyone on the planet has ANY ideas, I'd LOVE to hear them
Thanks
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Senior Member
Joined: Dec 2014
Posts: 448
Likes: 3
From: CALIFORNIA, UNITED STATES
2003 S430, 2014 E350
I'm from another planet, but I'll help you anyways. 
Try to lift the car up, maybe you have a leak when your struts extend. Get a jack and lift each tire one at a time.
Try to lift the car up, maybe you have a leak when your struts extend. Get a jack and lift each tire one at a time.
Senior Member
Joined: Apr 2012
Posts: 432
Likes: 96
From: Just north of Detroit,Michigan
2012 E350 4Matic P2
Put the old relay back in as long as it was still working when you swapped it for the new one. Hard to believe that a new relay would fail so soon but it is possible. If the pump is running all the time, it would eventually over heat, trip the relay and shut off.
Are you absolutely certain that what you hear running is the airmatic pump??
Good luck,
Bob
Are you absolutely certain that what you hear running is the airmatic pump??
Good luck,
Bob
What I would do is remove the air pump relay completely then drive the car to listen for the sound. I bet that it is still there. Since your SDS shows no faults, my guess is that you have nothing to worry about. If the system starts to collapse while driving, you can always pull over and put the relay back in but I doubt that will be necessary. You should have your answer soon enough.
Good Luck,
Bob
Newbie
Joined: Nov 2024
Posts: 13
Likes: 0
From: SC
2017 GLS450
So it's been a while but here's my update on this!
I am determined to find out what's up here and I actually ended up buying a complete MB Star Diagnostics System (lol, yes I did)
I ran all the Airmatic tests and the Star system tells me that everything in that area is working and running perfectly I was really hoping I'd find an error and/or leak but nope, all is well......
SO..... What the hell can it be now?
To recap, I drive the car, the pump comes on and pretty much stays on. I come to a stop or light, it spits out a little air and stops. I pull away, it comes on! I drive at 30 locally, it's on, I drive at 100, it's on.....
If anyone on the planet has ANY ideas, I'd LOVE to hear them
Thanks
I am determined to find out what's up here and I actually ended up buying a complete MB Star Diagnostics System (lol, yes I did)
I ran all the Airmatic tests and the Star system tells me that everything in that area is working and running perfectly
I was really hoping I'd find an error and/or leak but nope, all is well......SO..... What the hell can it be now?
To recap, I drive the car, the pump comes on and pretty much stays on. I come to a stop or light, it spits out a little air and stops. I pull away, it comes on! I drive at 30 locally, it's on, I drive at 100, it's on.....
If anyone on the planet has ANY ideas, I'd LOVE to hear them
Thanks
If you didn't find an "issue" did your compressor bomb from the excessive running or has it held up, supporting the other theory that it is more normal than we thought?
Thanks!
MBWorld Fanatic!
Joined: Dec 2012
Posts: 2,474
Likes: 439
From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
The car automatically lifts at highway speed, then lowers at slower speeds. It is possible to have a leak in a strut diaphragm that leaks at the higher level, but not at the lower level.
You need to put on your science hat, and do some research.
With the car parked and off on level ground, measure ride height (top of fender opening to ground) on all four corners, writing down the values.
Start the car, and remeasure each corner, writing down the values. Are they different? Is the compressor running?
Turn the car off,wait for an hour, and remeasure. Any change?
Start the car, and use the dash button to lift the suspension. How long does it take for the car to stop rising? Does the compressor stop? Remeasure, writing down the values.
You need to put on your science hat, and do some research.
With the car parked and off on level ground, measure ride height (top of fender opening to ground) on all four corners, writing down the values.
Start the car, and remeasure each corner, writing down the values. Are they different? Is the compressor running?
Turn the car off,wait for an hour, and remeasure. Any change?
Start the car, and use the dash button to lift the suspension. How long does it take for the car to stop rising? Does the compressor stop? Remeasure, writing down the values.
Newbie
Joined: Nov 2024
Posts: 13
Likes: 0
From: SC
2017 GLS450
The car automatically lifts at highway speed, then lowers at slower speeds. It is possible to have a leak in a strut diaphragm that leaks at the higher level, but not at the lower level.
You need to put on your science hat, and do some research.
With the car parked and off on level ground, measure ride height (top of fender opening to ground) on all four corners, writing down the values.
Start the car, and remeasure each corner, writing down the values. Are they different? Is the compressor running?
Turn the car off,wait for an hour, and remeasure. Any change?
Start the car, and use the dash button to lift the suspension. How long does it take for the car to stop rising? Does the compressor stop? Remeasure, writing down the values.
You need to put on your science hat, and do some research.
With the car parked and off on level ground, measure ride height (top of fender opening to ground) on all four corners, writing down the values.
Start the car, and remeasure each corner, writing down the values. Are they different? Is the compressor running?
Turn the car off,wait for an hour, and remeasure. Any change?
Start the car, and use the dash button to lift the suspension. How long does it take for the car to stop rising? Does the compressor stop? Remeasure, writing down the values.
Edit: I'm still not getting the pressure release burst after parking, that I'm used to hearing, so I'm guessing there's still something hiding in the system that's not quite right.
This forum has been a lifesaver and I genuinely appreciate your input!
Last edited by QuackQuackBlast; Nov 14, 2024 at 11:02 AM.
MBWorld Fanatic!
Joined: Dec 2012
Posts: 2,474
Likes: 439
From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
All air enters and exits the Airmatic system through the system air filter. There is a small hose that runs from the compressor up to a small air filter (which is actually a small in-line fuel filter) up inside the fram or on the side of the radiator. The air tube at the compressor is actually a molded rubber piece, and that piece is prone to failure, or, as the Brits say, perishing. Unfortunately, the failure seems to often be hidden on the back side of the rubber piece, so you don't see the failure. When this piece fails, or the rubber tube fails, or the filter is no longer on the car, it is possible to get water (and dirt) into the Airmatic system.
Built into the compressor is a chamber filled with desiccant pellets. Clean atmospheric air should enter through the filter and flow through the dessicant chamber. where moisture is absorbed. When the air is vented through the compressor, it flows back through the desiccant chamber, where it removes come of the absorbed moisture. The system keeps the Airmatic system dry, prevent corrosion in the valve block and other units.
When the intake system is open to water, the desiccant pellets will be overwhelmed, and the excessive moisture will cause corrosion, especially in the valve block, pressure relief valve, etc . If the corrosion doesn't cause enough problems, freezing temperatures will cause ice in the valve block, with major malfunctions.
It is not a really difficult job to remove and refurbish the compressor, basically installing a new piston ring, cleaning everything up, and replacing or refreshing the desiccant pellets. The piston ring kits were available for about $25, and desiccant pellets are cheap.
Built into the compressor is a chamber filled with desiccant pellets. Clean atmospheric air should enter through the filter and flow through the dessicant chamber. where moisture is absorbed. When the air is vented through the compressor, it flows back through the desiccant chamber, where it removes come of the absorbed moisture. The system keeps the Airmatic system dry, prevent corrosion in the valve block and other units.
When the intake system is open to water, the desiccant pellets will be overwhelmed, and the excessive moisture will cause corrosion, especially in the valve block, pressure relief valve, etc . If the corrosion doesn't cause enough problems, freezing temperatures will cause ice in the valve block, with major malfunctions.
It is not a really difficult job to remove and refurbish the compressor, basically installing a new piston ring, cleaning everything up, and replacing or refreshing the desiccant pellets. The piston ring kits were available for about $25, and desiccant pellets are cheap.
Newbie
Joined: Nov 2024
Posts: 13
Likes: 0
From: SC
2017 GLS450
All air enters and exits the Airmatic system through the system air filter. There is a small hose that runs from the compressor up to a small air filter (which is actually a small in-line fuel filter) up inside the fram or on the side of the radiator. The air tube at the compressor is actually a molded rubber piece, and that piece is prone to failure, or, as the Brits say, perishing. Unfortunately, the failure seems to often be hidden on the back side of the rubber piece, so you don't see the failure. When this piece fails, or the rubber tube fails, or the filter is no longer on the car, it is possible to get water (and dirt) into the Airmatic system.
Built into the compressor is a chamber filled with desiccant pellets. Clean atmospheric air should enter through the filter and flow through the dessicant chamber. where moisture is absorbed. When the air is vented through the compressor, it flows back through the desiccant chamber, where it removes come of the absorbed moisture. The system keeps the Airmatic system dry, prevent corrosion in the valve block and other units.
When the intake system is open to water, the desiccant pellets will be overwhelmed, and the excessive moisture will cause corrosion, especially in the valve block, pressure relief valve, etc . If the corrosion doesn't cause enough problems, freezing temperatures will cause ice in the valve block, with major malfunctions.
It is not a really difficult job to remove and refurbish the compressor, basically installing a new piston ring, cleaning everything up, and replacing or refreshing the desiccant pellets. The piston ring kits were available for about $25, and desiccant pellets are cheap.
Built into the compressor is a chamber filled with desiccant pellets. Clean atmospheric air should enter through the filter and flow through the dessicant chamber. where moisture is absorbed. When the air is vented through the compressor, it flows back through the desiccant chamber, where it removes come of the absorbed moisture. The system keeps the Airmatic system dry, prevent corrosion in the valve block and other units.
When the intake system is open to water, the desiccant pellets will be overwhelmed, and the excessive moisture will cause corrosion, especially in the valve block, pressure relief valve, etc . If the corrosion doesn't cause enough problems, freezing temperatures will cause ice in the valve block, with major malfunctions.
It is not a really difficult job to remove and refurbish the compressor, basically installing a new piston ring, cleaning everything up, and replacing or refreshing the desiccant pellets. The piston ring kits were available for about $25, and desiccant pellets are cheap.
Thanks again!
