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Discussion Starter #1
:(okay so i've had a 02 s430 for about 2 months now and yesterday after turning it off i notice a humming noise that turned into an inconsistent thump directly between the passenger side headlight and passenger front tire. after looking around on here wasn't able to find much that seemed similar the sound is similar to a broken bladed fan and is inconsistent it makes the humming noise then starts to thump then back to humming and so on i did see that the location seems to be the same location where the airmatic compressor is but the suspension is fine and the car opperates well. no new messages either. what could be wrong? did i buy a lemon? PLEASE HELP :confused::confused:
 

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It could be the airmatic pump or valve block going bad - but first, I'd check the mounting bolts for the pump and the valve block, and see if they are tight.

Your airmatic pump should not run most of the time; if the problem is pump-related, it could be that the airmatic relay needs to be replaced.

Please see the W220 S-Class Encyclopedia sticky at the top of the forum for more information on airmatic and the relay.
 

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Discussion Starter #3
i did read that a bit i will revisit it but i'm thinking it sounds like something may be broken or out of place the thumping noise is so inconsistent that i couldn't imagine it being a relay but i'm going to revisit the encyclopedia sticky on airmatic hopefully it helps i'm going to have to figure out how to get to where the compressor is i don't know anything about maitnence on a merc benz
 

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problem sounds like the isolation mounts on the pump. the pump is heavy, Mercedes designed a little suspension system for it. it uses rubber bushings and a spring at each mounting point to float the pump and isolate the vibrations, over time the rubber deteriorates and the springs sag & the brackets get closer together, eventually they can knock into each other, intermittently at first, think that's what you're hearing.

many times when people hear the pump knocking they think it's the pump itself, new pump comes on a new bracket with new suspension mounts, so replacing the pump will solve the problem, but if you can just repair or replace the mounts it can be fine again if the knocking is the only problem. I repaired mine by stretching out the springs & adding rubber bushings made from rubber hose, now it's back to me barely hearing it :)
 

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Thanks for the detail, turbocad - I recalled some problems reported with the pump mounts, but couldn't remember the specifics.
 

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Discussion Starter #6
Thank you that seems helpful do u have any idea wha I should look for and what to go thru to get to the compressor I'm assuming I'll have to take the tire and wheel well panel out but not sure what exactly I should be looking for the pump or the compressor they must be near by considering where the sound is coming from. And the last couple times I drove it it has been quiet since so I'm thinking I should fix it before it goes back to huming and knocking
 

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yes, exactly, remove the wheel then the fender liner. the pump and valve assembly is right there. this is easier than removing the front bumper and provides enough access really, not sure if the mounts are available separately, if they are then it might be a good idea to pick up a set before taking it all apart
 

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what to look for would be to shake the pump, if you feel it knocking against another bracket you'll know, also look at the mounts themselves... the spring should hold it high enough that it's centered in the bracket... if you see the bracket is sitting low close to the lower bracket that's a problem. also because this is kind of a floating suspension it's possible it will knock while parked on some angles and not on others IE:; cars leaning to the right it knocks but leaning to the left it doesn't.
 

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Discussion Starter #9
Okay so I found the compressor and pump and they both looked normal and equally spaced on the bracket but now the airbags have completely depleted so the car has lowered to the point where its not driveable and the esp, break assist and airmatic notices all came up :( is it time for to go to the shop? Seems like a major problem
 

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when you start the car again after it's on the ground does the pump run at all & try to fill the airbags, or is it doing nothing?
 

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Discussion Starter #11
Okay just checked the fuses for the air compressor its blown and blew the one I changed it to does this point it to the compressor relay where is it and where can I buy a new one? I'm trying my best to avoid a shop though I know I may have to take it there anyway any thoughts?
 

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If you're trying to avoid the shop, just buy a new airmatic pump and relay and install it.
If your shop is cool with you buying your own stuff and installing it themselves, that at least saves you their markup on the item and just becomes about 2 hours labor.
 

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Discussion Starter #13
it doesn't fill at all i just replaced the blown 40amp fuse with another and it blew it as well. i'm assuming its the relay but i have no clue i took the fuses out all together until i know whats blowing them:( just had it towed back to my house so i'm open for ideas as to what to do before i make my appointment with the shop for mondayish
 

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The relay for the airmatic system is a known failure item, I would replace the relay first - if it has shorted out it could also cause the fuse to keep blowing. Then after you replace the relay install another fuse. If the fuse blows again, then the short is likely in the pump itself.

The relay normally shorts out keeping the pump running until the pump burns itself out, you can read about all of this in the encyclopedia section of the sticky if you have not done so already.
 

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yeah, now it does sound like the pump might have just went, def worth trying the relay at least, but unlikely I think that would cause the fuse to blow, that's most likely the pump itself
 

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Discussion Starter #16
okay so i'm part shopping now should i be looking for the compressor or the pump or is it one and the same? i attatched a link to a part that if its the right one i'll be buying. i've bought two new relays and i'm ready to get this fixed and get my car back on the road someone let me know if this is what i should be looking for thanks Mercedes w211 w219 w220 Suspension Air Compressor GENUINE new | eBay
 

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judging from first it being loud, then it blowing the fuse repeatedly while trying to raise the car afterward, then yes, it's a very good guess that the pump is shot. I would also at that point start shopping for a pump/compressor ( yes, same thing).

one way to confirm beyond a doubt it's the pump would be to unplug it, then run the car with a new fuse, if the fuse doesn't blow then plug the pump in and start it again, if it then blows you confirmed 100%, but even without that, at this point it's probably already like 98% sure I'd say :)
 
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