N_Jay

2008 GL320 185K miles
Left Rear air spring and shock replaced about 5 years ago.
Right Rear shock replaced about 2 years ago.
Front air shocks replaced a year ago.

Symptoms:
Car overall lower than normal.
One corner (right rear) much lower than normal,
- This corner always sits a little low because I need a calibration
- This corner is the oldest air-spring
Car would not raise nor level last week and gave a "Compressor Cooling" error.
Car sat for the week and maintained about the same level. (Although tilted.)
Car raised most of the way when the lift button was pressed, but did so very slowly and gave a "Compressor Cooling" error.
- Car was most of the way raised and level at that point.

My thought;
a) A slow/weak compressor
and also (maybe)
b) A slow leak in the right rear air spring.

Thoughts before I tackle the compressor first?

chassis

Calling the experts @BlownV8 and @Max Blast

BlownV8

Have you ever replaced the air compressor? If not, it may be time. The first thing I would do is change out the right rear spring and then see if that makes a difference. The airbags are affordable and it's a 5 min DIY. If the compressor is still having difficulty, it's probably time to replace. Seems like that's around the mileage my compressor went out.

Max Blast

The compressor cooling is its “replace me” warning.
also replace both rear bags, 5 yrs is outside useful service life.

N_Jay

Doing the compressor first, since after it leveling up it stayed there.
Beside I got one st a great price.
It looks as easy as a rear bag anyway. .
Also replacing the relay and filter as a precaution.