air suspension leaks sometimes when not car not on

I have a 1997 Lincoln towncar with the air suspension. After parked for overnight I found the car sagging in the rear so I thought a air bag went out so I thought I would take it in to get fixed but the next few nights nothing happen the car stayed level then the next night it went down then the next few nights it stays level. I took it to the dealer and they told me they see nothing wrong and kept it over night and it did not go down. It is like a roll of the dice if it stays level or goes down. I sprayed the air bags and the lines to them with soap water to see if I could find any leaks but I did not see anything. The compressor is buried so unless I know that is the problem I am not going to rip everything apart to not find a leak or is that where I should be starting. If the car is running everything stays level and no light is on. Any one else have this problem? Sorry I do not want coils in the car I like the air suspension.

I have a 99 continental with the air leveling suspension. I had the same thing with the car sagging sometimes after being parked for a long time or over night. I think that is has to due with the bleeding system. Every time you shut it off it bleeds pressure out of the system and the valve either gets stuck open a little or it just bleeds out too much and then you have an embarrassing:shakehead looking car. I used to shut the system off in the trunk after it pumped up and it would stay level for a week then I would do it again. I asked the dealer if they could change the programming so it wouldn't bleed out any but they said that it couldn't be done. Now mine need replaced because they are old and cracked and seeping air out slowly.

So if I turn off the air system before I shut the car off and it does not go down that would tell me that it is not air bags but a bleeder valve. But from what I can gather this valve is in the compressor and not a repairable part but just replace the whole compressor

I would say that after a week or so that it is safe to assume that you have no leaks to speak of. So if there are no leaks, then I would think that it has to be the computer letting out too much air or the bleeder valve sticking. Just my thoughts. I lived with the same thing for years.:screwy: