This post start with MB W211 owner’s issue with Airmatic, then followed two pieces of advice from experienced technicians. One of the technician mentioned the well-known DAS Xentry diagnostic equipment. See details as follows.
Airmatic issue Benz W211:
When the car is parked overnight at normal drive height, the rear of the car will drop on both sides equally approx. 3 to 4 inches. When started in the morning, the compressor will pump it up right away.
When parked overnight in the raised position, the rear of the car will not drop at all. So I guess, there is no leak in the air springs.
I can see on the schematic that there are 2 solenoids in each rear air spring. For example, on the driver side, Y53/1y1 is for the air dampening, Y53/1y2 is for the level. Which of the two closes at the raised position and keeps the air in the air spring? Is it possible that both valves are open at normal drive height after the car is parked, or is one of them supposed to be closed but leaking? Is it possible that the check valves or solenoids in the compressor are leaking and the air can escape there in normal drive height position if both air spring solenoids are open. I am at a loss and don’t want to throw money at the problem without fully understanding it.
Btw, I have soap tested the valve block next to the compressor, the line from the compressor to the valve block, the divider at the rear axle and all 3 accumulators, but have not seen any leaks.
– It’s a complicated system–if you have checked WIS, you will see a comment on how to connect the DAS Xentry diagnostic equipment—-follow the instructions!!
– The following picture explains solenoids, may need to replace rear struts (consider Arnott aftermarket) but before doing so follow advice given, have someone pull fault codes.