Jan AMG

Alright so we found one more thing that is weird - The Airmatic compressor (I think) makes a "phew" sound, very loud, like there would be some excess air that it needs to blow off. Anyone experienced this? The car is 2008 S500L 4Matic with 10.000 miles on it.

Diesel Benz

When does this happen? My car makes this "phew" often when I leave the car and specifically if several persons step out so that the car needs to level suspension to a significant load change. In this case Airmatic literally blows air off the air springs.

I assume that you consider the sound being loud when comparing to the very quiet S500 engine etc. I guess you cannot hear the sound except if a window is open or if you have stepped out of the car?

Jan AMG

It happens exactly as you describe. You can hear it when you step out (with engine on or engine off) or when passing objects that can give you echo at low speeds with windows down.

It is loud when comparing to the S500 engine and also quite silent hissing sound when the car levels itself after engine shutdown.

Are you saying this can be normal? I have never heard it on any car with Airmatic before I don't mind the sound if it isn't indicating that the compressor or something relevant is calling for replacement

Franman

my GL makes the same hissing and PHEW sounds when exiting the car - guess it's normal but nothing in instruction book about it

Jan AMG

OK thanks this makes me feel better!! Good to know I'm not alone few more troubles and I will replace the S500 with something else ... but what? Another S? CL or GL make sense too. But it is such a great car I don't want to change it. I hope MB has improved their reliability significantly!!!

Trey

My previous 05 S500, 06 E500 and current 07 S550 all do this. So does my parents Jaguar XJ. I am certain it is completely normal. If you watch the car, you will see it lower at the same time.

RajwanyS550

It like a Beast letting out its Breath.

capitalexpress

100% normal... its the airmatic...mine does it all the time

lkirchner

Not to worry since this is normal

ajm0623

me, too! me, too! does it all the time. '07 with 19,000 miles. car runs like a dream. time after time.

Jan AMG

I like this one!

Jan AMG

Thank you all guys for reassuring me! It's valuable to be able to share and ask.

carsnob

due to too much gas!

Mercedes22

Mine to.

vintagefefe

A BOV would sound MUCH MUCH louder than what the airmatic could ever make....unless it's blown hehehe...