I own a 2007 XJ8L with 45,000 miles and have noticed an occaisional issue that seems to worsen with time. After driving home from work, about 28 miles, my air compressor makes a popping sound when I turn the engine off. This can last up to several minutes and I have counted up to 90 pops before it stops. I have also noticed my front end raising when stoped at red lights and sometimes when starting the car in the morning. As luck would have it, my dealer claims they cannot duplicate the issue. I recently had it in the dealer for service, they claim they cannot duplicate, but it has now happened every day since I got it back, I will be going back shortly before my warranty runs out.
Has anyone here had the same issue? Any ideas on what it may be?

 

moving you to the correct area of the forum - the xj8/xj6 section. There's a huge (133 post) thread related to the air suspension...dig in!

 

Since I posted this, I have been paying more attention to what I am hearing when I turn the car off. It seems that the compressor runs for a few minutes when I turn the car off. I hear the sound most predominately at the rear left tirewell. Along with the running compressor I hear a series of popping noises that occur about once every 2-3 seconds. When the compressor turns off the pops are very rapid for about 2 seconds and then they stop entirely. Has anyone reading this post experienced the same? Would this be considered normal operation?

 

The compressor fills a reservoir tank in the trunk. The popping could be the pressure release valve. I do beleive compressor, each shock and the reservoir has them. Then the car sits the system checks the height of the car at predetermined time intervals. If one of the sides is low it will release pressure in the other 3 to level the car. This prevent wearing down the battery incase of a leak. When I start my car the compressor does turn on and run.