Airmatic suspension
#1
Member
Thread Starter
Airmatic suspension
Hi, I have a 2012 GL 450. Everything seems to be fine but when I drive every once in a while on the right front side, I hear a hissing noise. It does it for a few seconds and then it stops and then every other once in a while it does it is this normal or is there something going on?
#2
MBWorld Fanatic!
If it’s a hissing noise coming from the right front (us passenger side) fender folllowed by a whoosh after opening a door that is normal. Your valve block is venting excess pressure overboard through the compressor intake pipe.
if it’s a a hissing noise that comes and goes independently of opening a door and leads to that corner being noticeably lower than the others, that is not normal and could be a leak in an air spring.
the overnight sag limit is 10cm.
if it’s a a hissing noise that comes and goes independently of opening a door and leads to that corner being noticeably lower than the others, that is not normal and could be a leak in an air spring.
the overnight sag limit is 10cm.
Last edited by Max Blast; 06-14-2024 at 08:33 AM.
#6
If it’s a hissing noise coming from the right front (us passenger side) fender folllowed by a whoosh after opening a door that is normal. Your valve block is venting excess pressure overboard through the compressor intake pipe.
if it’s a a hissing noise that comes and goes independently of opening a door and leads to that corner being noticeably lower than the others, that is not normal and could be a leak in an air spring.
the overnight sag limit is 10cm.
if it’s a a hissing noise that comes and goes independently of opening a door and leads to that corner being noticeably lower than the others, that is not normal and could be a leak in an air spring.
the overnight sag limit is 10cm.
#7
MBWorld Fanatic!
How about if both front sides are low. Like maximum low? My car was parked over several days and one morning I come out and see the front tires are just about at the top of the wheel opening. Started the SUV up and it immediately rose to normal. It has stayed at normal after a little driving and again parked for several days.
if you have visible settling overnight, i say you’ve got a leak.
go hose both front bags down with leak detector spray or as Eric would say, soapy wooder.
if you continue this kind of behavior you will burn out the compressor in no time.
Last edited by Max Blast; 06-16-2024 at 03:07 PM.
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#8
Sag limit is 10 cm overnight. That is a very generous limit.
if you have visible settling overnight, i say you’ve got a leak.
go hose both front bags down with leak detector spray or as Eric would say, soapy wooder.
if you continue this kind of behavior you will burn out the compressor in no time.
if you have visible settling overnight, i say you’ve got a leak.
go hose both front bags down with leak detector spray or as Eric would say, soapy wooder.
if you continue this kind of behavior you will burn out the compressor in no time.
#10
Also, the fact that it was down equally on both sides suggests it wouldn't be a leak in the boot, right? I don't know how the air lines run, but it only affected the r/l front, too.
Last edited by Elbeau; 06-17-2024 at 11:02 AM.
#11
MBWorld Fanatic!
Thanks. It was parked where I normally do and no change over the past several days. But, I'll keep an eye on it. Doesn't seem like using a leak detector now would help. I'm measuring the gap between the top of the tire and the wheel well in the meantime.
Also, the fact that it was down equally on both sides suggests it wouldn't be a leak in the boot, right? I don't know how the air lines run, but it only affected the r/l front, too.
Also, the fact that it was down equally on both sides suggests it wouldn't be a leak in the boot, right? I don't know how the air lines run, but it only affected the r/l front, too.
the third reason, although less likely is that you have a leak in the valve block itself.
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Elbeau (06-17-2024)
#12
Any possibility it could be battery related? Although the batteries (main & aux) are fairly new, the SUV has gone from being used regularly to only occasionally. I do have a dash cam running in parking mode that is triggered often from passing cars. I know the battery can cause all sorts of weird events. No low battery or charging warnings, though and car starts normally.
#13
MBWorld Fanatic!
The airmatic suspension will check and if necessary; auto level every time a door opens. If you have a door sensor that is malfunctioning that could give erroneous commands to the airmatic to go level itself and thus deplete air pressure in the central reservoir.
but I don’t see how it could be battery related.
but I don’t see how it could be battery related.
#14
The airmatic suspension will check and if necessary; auto level every time a door opens. If you have a door sensor that is malfunctioning that could give erroneous commands to the airmatic to go level itself and thus deplete air pressure in the central reservoir.
but I don’t see how it could be battery related.
but I don’t see how it could be battery related.
#16
Super Member
#17
My mechanic bought them and i didn't ask because he usually uses OEM unless very overpriced and he guarantees his work. Based on the overall price, he didn't use OEM, but high quality aftermarket. Looking at them installed i couldn't see any obvious differences. I did see a label. I'll edit the post if i see a brand name.
Last edited by Elbeau; 06-28-2024 at 01:17 PM.