I have an air leakage on my E220 cdi -03. It seems like an valve problem since it sometimes doesn't leak and sometimes the tail is low after a night's stand. Has anyone had the same problem and could you tell where are the valves of the system. There were some pics about the system in this thread but a part list could also be helpful. If the valves are in the springs am I looking to whole spring change? The cost of one air spring was in Finland about 500 €.
BTDT. What you have is a leak in the spring and it is a small hole. At night power off the temp cools the air volume is reduced the rear sags a bit and the air leaks out then the car settles on the chassy. It is only a matter of time before you have a total failure of the air spring.
I have been down this road with the dealer under warranty. The first time I brought it in "could not duplicate". NUTS. I waited until the warning came on every time I started the car then drove it in and left it running so they could see and verify the warning.
I went back 2 days later after they replaced the air pump in the left front fender telling me the pump had failed. (nuts again,, the air pump always pumped it up after start therefore the pump works). However when they drove the car out the rear had totally collapsed. I refused the car and the took it back into the shop and confirmed the air springs had failled.
Summary ,,, just a matter of time before your air springs fail
If they sold the E500 w/normal steel springs I would prefer it for the reliability. I consider the air suspension unreliable with so many strut and spring failures. This might not be an issue is it weren't $1500+ for each failure.
Now that I have had my rear air spring fail I am waiting for the front struts to fail. They have to be running a close 2nd.