Hi there, this is my first post so here goes. I know this issue has been talked about extensively in these forums but I havent been able to find out a true fix.
I just bought a 2000 S500 with airmatic this week. The car is beautiful and only has 46k miles. Every morning when I go out to the car it sits super super low on all fours. Almost as if the tires are touching the inside aprons. When I unlock the door it starts to raise and after I start it it takes only 30 seconds to get to normal height. I don't have to push the button.
It takes about 6-10 hours for the car to sink so low, but once up it runs beautifully. The air compressor is not running extensively and I only hear it when I start up the car in the morning.
pull the hood release and leave the hood unlatched the night before. youll do a test the next morning and need the hood unlatched
the next morning when its low, open the hood and spray soapy water on the front shock towers (black area with hose coming out of center) using a spray bottle.
watch the soapy strut towers closely, as you get someone else to then unlock and start the car...if you notice bubbles as the car rises, you have a leak at the top of the shock towers (common issue and there is a seal kit).
if you dont see bubbles you have a leak but its elsewhere such as the bottom of the struts or maybe in a line
The valve is $300 from any MB dealership. My mechanic charged $200 to put it in. But he did try initially to put a seal on it but it didn't work so we ended up replacing the whole valve.
My MBechanic has had a bunch of these so he had an idea on what he was doing. The way he found the leak was that they put some sort of colored gas into the air line and then looked for the leak.
I have heard that the leak may also be in the compressor and a new compressor woul be needed. They're about $300 on eBay. Good luck!