Going through this and thought I would share.

Bought an 07 for my dad, 130k. Compressor was changed approx 30k miles ago.

After 4 days the rear was almost on the ground and front was slightly higher.

Disconnected the battery, after 2 days the rear dropped exactly the same amount. The fronts dropped slightly but one more than the other.

I'm guessing rear valve block since both rears dropped the same amount. Maybe the desiccant from the failed compressor dryer messed up the valve block.

Also guessing the front struts have separate leaks.

I'm going to dive in next week. I'll give an update.

 

I am not looking forward to suspension issues, I half want to rebuild the compressor before I have problems

 

Resolution:

Since the car is for my father he wanted all parts replaced new.

Changed out front air struts. Front held up fine.

Changed rear valve block and the rover stopped losing height over night.

So the diagnoses was correct.

In final(after changing the above parts) I ended up also changing rear air struts, inner and outer tie Rod ends, brake rotors, pads, all fluids, Trans service with metal pan, and the thermostat housing cluster.

3 observations/issues:

- Inner tie Rod ends come in different lengths depending on year. Apparently sometime in 2006 they changed. I ordered mine through world Pac for a 2007 and they were correct. Decided to order a set for my 06' and Erik at lucky8 advised that they come in different lengths and used my VIN for part ordering.

- I pinched an airline at the front and before putting the tires back on I wanted to see if the line was compromised. Started the vehicle and activated the air suspension, got faults. Once the 3 was on the ground the suspension height was whacked. I had to re calibrate the suspension. So if you don't have the proper tool, don't do what I did.

- when fitting the metal pan a few of the bolts are harder to reach and I ended up using a universal joint on the bolts. I did not get the same torque on a few and after the first night had a leak. I ended up going back and re torquing and seems to be fine.

 

Were you able to recalibrate without accessing the computer? I've always been curious if this could be done without the the additional software.

 

I had to use an Autologic to restore the calibration settings. So yes, I had to access the computer. I also lowered it an inch after the restoration as my dad has bad knees and I figured it would be easier for entry.