Luftkompressor Volvo XC90

Our technical advise for the air supply device:
1. Increased noises while the compressor is running may be caused by a non-functioning compressor mounting. 
Change the rubbers and springs of the  mounting in any case.
2. A porous intake hose often is the cause for a breakdown of the compressor.  
Change the intake hose and preferably also the filter and noise absorber, because we do not want the compressor to breakdown because of these.
3. Change the relays before installing the compressor even if it seems to still work. 
This is also a specification by the car manufacturer. Be sure to change the right relays. 
Relays look similar, that is why there is a risk to change the  wrong relays.
4. Be sure to check whether the system is leakproof after repairing.
The easiest way to do this is to park the vehicle. Wait for the system to automatically re-adjust if your car has this feature.
Then measure the heights from the ground to the lower edge of the fender as exactly as possible and take notes. 
On the day after measure these heights  again and compare them with the ones before. Even a small difference will lead to a damaged compressor and damaged valves in the long run.
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When driving with a leaking suspension for a long time it needs to be assumed that the compressor is running more often than normal. The increased number of cycles of powering on and off is likely to already have damaged the compressor.  Depending on the duration of that condition you should change the relays and check the performance of the compressor to be on the safe side. After the vehicle stood overnight the compressor normally doesn't need to run more than 20 to 30 seconds for the system to be ready to start.