Short answer
Measure the drop before choosing a repair
Photograph all four corners on level ground before starting the car, and note how long it was parked. On air-equipped vehicles, repeated one-corner or axle height loss needs leak isolation. A car that rises again can still have a leak; compressor replacement alone does not explain where the air went.
What the symptom looks like
Owners often notice a wheel arch closer to the tyre in the morning, a low rear axle after the vehicle has carried passengers, or a car that rises after start-up and then repeats the same drop the next day. Photographing all four corners on level ground can preserve useful evidence.
- One corner drops while the other three remain stable
- Both rear corners settle
- The entire vehicle settles evenly
- Height changes only after a particular temperature or parking duration
- The compressor runs for a long time on the next start
Potential leak paths
Air can escape through the flexible air spring, an air line or fitting, the valve block or another sealed pneumatic path. A control valve may also allow air to move between parts of the system. Temperature changes alter air pressure, so repeatable measured height is more useful than a single glance.
- Porous or cracked air-spring bellows
- Strut or spring seal leakage
- Line or fitting damage
- Valve-block internal leakage
- Reservoir or supply-line leakage
- Incorrect height information or commanded venting that mimics a leak
Why the compressor may be a consequence
The compressor replaces air lost by the system. When a leak is present it may run longer and hotter, so an eventually weak compressor can be secondary damage rather than the original cause. Replacing only the compressor can restore lifting temporarily while leaving the leak unchanged.
Models and systems differ
S-Class, E-Class, GLE and GLS vehicles may use different AIRMATIC generations, and selected later SUVs combine air springs with E-ACTIVE BODY CONTROL. G-Class/G63 and C63 vehicles use coil springs, while some C-Class variants have optional air suspension. Confirm the fitted system before treating overnight height loss as an air leak.
Should you continue driving?
If the vehicle rises to normal height quickly and no tyre contact or red warning is present, a short careful trip to diagnosis may be possible. Do not drive if it remains very low, rises unevenly, contacts the body, rides harshly on its stops or displays a stop instruction.
Evidence-led process
How this Mercedes symptom should be diagnosed
- 1
Park on level ground, record ambient conditions and measure each wheel-centre-to-arch height.
- 2
Confirm whether the control system was left active and whether the vehicle commanded a level change.
- 3
Repeat measurements after a defined period to establish the pattern.
- 4
Scan height values and related suspension faults without clearing them.
- 5
Leak-test the affected spring/strut, lines, fittings and valve path.
- 6
Check compressor recovery only after quantifying the leak demand.
- 7
Verify normal height retention and compressor operation after repair.
Why a fault code does not prove a component failed
An overnight leak may leave no decisive fault code because the vehicle is parked and the pressure loss is physical. Conversely, a compressor run-time or level-control code can be the result of the leak rather than proof that the compressor started the problem.
When professional diagnosis is appropriate
Arrange diagnosis when the drop repeats, the compressor runs longer than before or ride height affects driving. Ask for measured height or leak evidence and confirmation of whether the compressor was damaged by the original leak.