Even when I first got the car, I would hear the pump run if for example I put a 400 lbs twink motor in the back, or if I parked on a slanted drive way overnight, or if my grown kids got I to the send row.

vote for correcting
 

If you have to get the pump cycling every day because of this leak then you might not enjoy a long life on that compressor. I might be wrong but set duty cycles aside and consider the frequent exercising will shorten the calendar life of your pump because it is still wear and tear on the pump internals.

You might reconsider and go ahead and correct the problem since the 40 minutes you need to do so is less time and less expensive than dealing with compressor replacement.

just a 2nd on the previous suggestion from pshovest.

My 2p on the subject:
1) A pump that never runs is not a good thing either...
2) I replaced my failed bag with an Arnott recently. Stays up no problem, bzut interesting thing is that there is no resistance to pulling the line out of the bag connector. I thought this strange at first but assumed there is more resistance when under pressure, and also it needs to come out again if the bag ever needs replacing.

on point #1, agree with you 100%
-however, the compressor will run because the system lets air out and depressurizes under normal conditions. Also, I would not believe anyone if they told me the air lines on their E70 were 100% sealed.

I observe that mine runs depending on the load as well as the attitude of the car when parked. I also observe that I don't get sag when the car is parked for many days at at a time.

simply suggesting that 15" of run time every day to re-pressurize is excessive compared with my experience

on point #2, I replaced both bags with Arnott's a year ago and I'm pretty sure that when I installed the split ring and compression nut on the bags the air line was not able to slide in and out of the bag as you suggest. I didn't torque mine on very tight to get the lines to seat securely. I did cut off the last 10mm or so on each when I changed them due to the pre-existing crimp of the previous compression fitting install.

I'm not sure how much of this line is there but I suspect I could go another couple of times with trimming the ends and still be good.

YMMV.

All good feedback

But there is no compression fitting on the line for Arnott bag? The instructions say to just slide the line in to the hole and pull back a tad to lock. Well mine didn't appear to lock, but it didn't come out either when the system was pressurised.

chalk it up to different Arnott bags?
 

this is what I have...

the Arnott TSB shows the compression fittings; identical to what was on my LCI. Don't know if it matters but I have a late June 2013 production date.

Arnott TSB

The PDF doesnt load for me...
I have an early 2010, so may be different.... Did you get compression fitting s supplied? My instructions said remove bmw fitting and discard.

Both Arnotts were replaced today in Mesa, X5 was ready around 2:30, picked it up at 4... looked fine in the parking lot. Stopped on the way home for about hour and a half, leveling was fine when I left. Backed into my garage at 6, and as soon as the engine was shut off the compressor kicked in and a loud hissing noise was audible. Saw a couple of DIY videos but the vehicle is too low to get under with a flashlight, will call the tomorrow. :rant:

I just feel better letting it all out here...

Lev