The most common signs of a leaking air spring are that the car sinks overnight, the compressor runs often or loudly, the ride height becomes uneven, a warning light comes on and there is a hissing sound near the wheel. Test with soapy water and replace the damaged spring as soon as possible.
1. The car sinks after parking
If your car is parked overnight and you notice that it sinks on one corner or the rear end hangs down, it is a clear sign that an air spring is leaking. The leak causes pressure loss in the air suspension system, and the car gradually drops, often on the same side each time. If the car stands lower after the night but rises again when the engine is started, that is a common symptom of worn air springs. How to measure the drop is described in the section How to test whether the air spring is leaking.
2. The compressor runs often or sounds loud
A healthy air suspension system should maintain stable pressure. If the compressor runs frequently or makes unusual noises, it is compensating for a loss of air pressure. This puts heavy strain on the compressor and can lead to overheating or motor failure over time. Read more about how air suspension compressors work.
We sell air compressors from WABCO, AMK, Arnott and Continental.
3. Uneven ride height or stiff suspension
When an air spring starts leaking, the pressure drops and the car develops uneven height between front and rear or between the left and right sides. You may also notice that the car feels stiff, a sign that the air spring is no longer damping properly. A common cause is cracked rubber from years of use or exposure to winter road salt. On older cars with high mileage, the protective boot around the air spring can also be cracked or worn, which lets dirt into the air spring.
4. Warning light on the dashboard
Cars with air suspension normally have a warning indicator for the suspension system. On the Mercedes W220, the instrument cluster can show “AIRMATIC VISIT WORKSHOP!”, which reportedly means an electrical fault in Airmatic/ADS (fault codes are read with a diagnostic tool), or “AIRMATIC STOP, CAR TOO LOW!”, which means the car is sitting too low: stop and avoid driving further. Other models may show other messages. In many cases the cause is a leaking air spring or a fault in the valve block. Read the fault code before you buy a part.
5. Hissing sound near the wheel
A hissing noise near the wheel arch after the car has been switched off points to a heavy leak. The sound may come from the air spring itself, a line fitting or the valve block. If you hear it right after switching off the engine, check the connections with a detergent solution as described in the test below.
How to test whether the air spring is leaking
The measurements below reportedly apply to the Mercedes W220. Other models may have other limits.
- Park on level ground. Measure the distance from the edge of the wheel arch to the centre of the wheel hub (or another fixed point) at all four corners and write the values down.
- Leave the car undisturbed for 10 hours and measure again.
- A drop of more than about 20 mm (about 30 mm in cold weather) over 10 hours points to a leak. For the Mercedes W220 this is stated as the limit value.
- Compare the right and left sides: when an air spring leaks, the whole axle often sinks.
- Soapy-water test: brush a strong dish-soap solution onto the connections and the air spring (do not spray). Small, slow bubbles can mean a damaged O-ring.
- A stuck compressor relay: the compressor runs all the time and the fuse can blow.
- A valve block that does not close (W220): the car sinks slowly but is partly held up by a check valve (residual pressure).
- A level sensor with a wrong reading: the car can sit too high or too low even though the pressure is normal.
Overview: symptom, cause and solution
| Symptom | Likely cause | Solution |
|---|---|---|
| Car sinks after parking | Leaking air spring | Check with soapy water |
| Compressor runs often | Air leak in the system | Inspect air springs and valve block |
| Uneven height | Pressure loss | Replace spring or valve block |
| Warning light on | Fault in the suspension system | Diagnose via OBD and inspection |
| Hissing sound at wheel | Leaking hose or spring | Replace faulty component |
| Stands lower after the night but rises when the engine starts | Leaking air spring | Measure the drop and test with a detergent solution |
| Cracked or worn protective boot | Dirt gets into the air spring | Have a workshop inspect it |
How to fix the problem
If you have confirmed a leak, replace the air spring as soon as possible. Driving with a damaged air spring risks damaging more parts. If you are unsure, have a workshop assess it.
Replacing both springs on the same axle at once keeps ride height and load even; read why in our guide on why air suspension components should be replaced in pairs. At Luftfjädring24 you will find air springs from Arnott, Bilstein, BWI, Vibracoustic and Firestone, among others.
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Frequently asked questions
How do I know whether it is the air spring or the compressor that is faulty?
If the compressor runs often and the car still sinks, the air spring or a hose is usually the cause. The leak wears out the compressor. Check the air springs with soapy water before replacing the compressor.
Should I replace both air springs on the same axle?
Yes, replace both springs on the same axle at once. That keeps ride height and load even.
How long does an air spring last?
It depends on climate, driving and age. The rubber ages even when the car is not used, so many air springs start leaking after a number of years even with moderate mileage.
Can I replace an air spring myself?
On many cars it can be done with ordinary tools, but the car must be lifted safely and the system handled according to the manufacturer’s instructions. If you are unsure, have a workshop do the job.
How do I find the right part for my car?
Choose your car make and model in the menu or search for the OE number on your old part. We ship from our Stockholm warehouse to Sweden, Norway, Denmark and Finland.
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