Just noticed last night that my car's front passenger side is sitting a bit low and after starting the car the height seems to go back to normal. The ride still feels smooth and there is no noise coming from the suspension. Could that be a sign of leaking air bag

 

By the way what does a completely failed air suspension strut look like? Does the upper part of the tire get in contact with the fender? Also, does the air suspension compressor engages when the car's engine is off?

 

No, the upper part of the tire will not come in contact with the fender when the air shock is completely deflated, and No, the compressor will not start with the ignition off. It's likely that you have a leaky air line connection. Please take a look at the excerpt from the factory repair manual below...

 

Thanks! I will check them. By the way, what is the best solution to repair a leaking air line connection? Or can I just live with it?