Frequency of air pump running?
Thread Starter
Senior Member
Joined: Apr 2015
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GLS450
Frequency of air pump running?
So, new 3722 pump and Arnott’s best valve block installed. Malfunction no longer displayed. I left car at maximum height for two weeks with no sagging. Now that I’ve started driving it again and it has returned to normal ride height it seems to me that the air pump runs more frequently than it should.
What’s normal?
What’s normal?
MBWorld Fanatic!
Joined: Jun 2010
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From: Emmett, ID, USA
2007 GL450
By the way, I never change the fittings when I service the system. Only change the fittings if they leak. I also spray the outside of the fitting with silicone before reconnecting, to protect and lubricate the o-rings.
Senior Member
Joined: Apr 2014
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2007 GL450
The OEM pump was not noisy.
The original pump and manifold was replaced in 2022 with a kit from FCP euro (arnott brand)
The new pump is louder, and can be heard when the GL is running (the GL engine is pretty quiet). Other users also reported louder arnott pump.
The original pump and manifold was replaced in 2022 with a kit from FCP euro (arnott brand)
The new pump is louder, and can be heard when the GL is running (the GL engine is pretty quiet). Other users also reported louder arnott pump.
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Joined: May 2015
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From: Allentown, PA
'08 GL 320 CDI
Sculler... maybe we could compare "run time" in the diagnostics? It wouldn't be definitive since there are multiple variables, though.
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MBWorld Fanatic!
Joined: Jun 2010
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From: Emmett, ID, USA
2007 GL450
The system is designed to use the reservoir to adjust ride height when your trip begins.
The pump is activated to refill the reservoir, but it waits until the engine is running in order to mask the noise.
If you hear the pump running every time you start up, the reservoir, or the hoses and connetions leading to it, are probably leaking.
The pump is activated to refill the reservoir, but it waits until the engine is running in order to mask the noise.
If you hear the pump running every time you start up, the reservoir, or the hoses and connetions leading to it, are probably leaking.
Senior Member
Joined: Apr 2014
Posts: 332
Likes: 70
2007 GL450
The system is designed to use the reservoir to adjust ride height when your trip begins.
The pump is activated to refill the reservoir, but it waits until the engine is running in order to mask the noise.
If you hear the pump running every time you start up, the reservoir, or the hoses and connetions leading to it, are probably leaking.
The pump is activated to refill the reservoir, but it waits until the engine is running in order to mask the noise.
If you hear the pump running every time you start up, the reservoir, or the hoses and connetions leading to it, are probably leaking.
on the other hand, replacing the pump and manifold is pretty easy if the front bumper cover is removed, basically plug and play.
Thread Starter
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GLS450
R&R reservoir
Looks like a very easy job but I’ll bet the reservoir is a very spendy part.
I’ll have to check my airline connections at the pump outlet, the valve block and the reservoir with soapy water spray again.
I’ll have to check my airline connections at the pump outlet, the valve block and the reservoir with soapy water spray again.
MBWorld Fanatic!
Joined: Jun 2010
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From: Emmett, ID, USA
2007 GL450
The reservoir is readily accessible. It is underneath, just forward of the rear bumper.
I highly doubt the reservoir would spring a leak. Far more likely is the connections, particularly at the valve block, or the line itself, if it got damaged.
I highly doubt the reservoir would spring a leak. Far more likely is the connections, particularly at the valve block, or the line itself, if it got damaged.
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,755
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From: Emmett, ID, USA
2007 GL450
I doubt it is worth tearing apart the interior to check the lines to the back.
I don't notice my air pump running on any regular basis.
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NGL450 w/EORP, S550
the pump should be almost silent, barely detectable at idle with an ear by the front right wheel. Doublecheck that you used all the rubber mounting pads and if so in the correct orientation.
Thread Starter
Senior Member
Joined: Apr 2015
Posts: 280
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GLS450
Finally…maybe
I’m evidently a slow learner but I think I have reached a successful conclusion.
The malfunction was displayed because some former owner had installed a $50 Amazon valve block and my air pump was weak by being over worked.
New 3722 Arnott pump and a 3823 Arnott valve block installed and malfunction display has never returned.
icarsoft MB 2 was very useful once I realized I had to erase the old DCT codes in Airmatic. I now have no DCT codes.
Thanks to all for your help!
The malfunction was displayed because some former owner had installed a $50 Amazon valve block and my air pump was weak by being over worked.
New 3722 Arnott pump and a 3823 Arnott valve block installed and malfunction display has never returned.
icarsoft MB 2 was very useful once I realized I had to erase the old DCT codes in Airmatic. I now have no DCT codes.
Thanks to all for your help!
Last edited by 1xsculler; Mar 1, 2024 at 02:28 PM.
