Matt S.

2014 GL450 X166 non ADS 77,000 miles
Compressor and valve block 2 years old
Rear struts and air bags 1 year old
Car doesn't appear to lose any air. Rides fine. Raises and lowers fine.
Recently my compressor seems to run almost all the time. When I stop at a light or sign, it stops. Once I'm moving again it comes back on.
Should I be looking for a leak somewhere?
Original front struts starting to go?

BlownV8

Yes and yes.

silvergl

The bags could still be bad, or it could be the valve block, although it appears that is rarely the issue. I replaced mine in a parts hunt to find my leak, turned out to be the bags. After replacing the compressor and valve block. All of it is pretty easy and cheap to do. You can probably put your ear to to each component and hear a leak, or try soapy water at all the connections.

L&N Caravan

Prior to throwing parts at it, grab a squirt bottle with dish soap + water and spray brass nuts/ferrules at each point of air connection including valve block. Any bubbles getting bigger or slowly appearing indicate air leak, hence a running compressor. Air lines are polyethylene which can provide stiction slip. Observe torque values when tightening brass nuts at bladder connections/valve body.

Suggest minimal driving b/c this constant running will significantly decrease air compressor life and/or fuse (which I still can’t find on my 2014 GL550 ).

If no leaks, agreed most likely front struts, but not necessarily. Had a new bag that had a leak - chased my tail for a bit and then bubble tested - viola! Bag still needing replacing though.

77k is not a lot of miles on these OEM struts - originals are built well. Though no pumping when at a stop sign is a reasonable cause for suspecting front struts.

A simple test to confirm…in the garage with a buddy, two jacks under vehicle’s rear lifts points. Spray strut towers down with bubble soap + mirrored lifting both sides - does pump come on? Any bubbling noticeable annywhere? If so, new struts on the menu.

About to change mine out as well for first time at 223k miles. I’ve got the front end clunk noise too so all new bushings/vertical bars on deck. When operating properly she’s one heck of a ride.

Matt S.

The line fitting on top had a tiny leak and of course a turn of the fitting stripped it out of the strut. I should've know better. I tried to helicoil it back in but no go. I have a pair of Arnotts on order. Hope that is the only thing. Can someone give me the torque specs for the top nuts, bottom mount, and the sway bar linkage? Thanks.