Hello All,

I posed this over in the GL forum as well (mistakenly) but it probably belongs here more than there.

I've got some familiarity with air suspension systems on my old Touareg and current Cayenne but I am now in the market for GLS and could use some input from the folks here. A '18 model at a MB dealership came up for sale kinda close to me and the sales guy sent over a couple pictures. One of them shows the car on the lot with the rear end sagging significantly. I raised the issue with him and even asked him how it was CPO'ed if the suspension sags. His response was that "they all do that when parked for an extended period of time". Now, in my experience this has never happened on any of the air suspension equipped cars that I've owned. It's a sealed system and if the car is sagging that means there's a leak. The sales guy is adamant that everything is ok and that it was properly checked over by the service department.

Usually, I would just chalk this up to the usual "sales guy not knowing the mechanics of the car he's selling" syndrome but he later sent over a picture of a brand new '22 GLS sitting on their show room floor that is also sagging in the rear.

What do you all think? Is there any validity to this? Is there any documentation to support his claims? I'm still hesitant to believe him.

 

That does not seem normal. I have a 2017 GLS 550 ( 98K miles ) and the air suspension compressor just went out. I could immediately tell that the vehicle was not sitting right. The dealership confirmed there was a leak ( which is common according to them) and the compressor went out. If you get to check out the vehicle in person, you should be able to tell if there is a warning light or not. Good luck with the search.

 

post the pics?

 

Here's the '18

and here's the '22

 

Just my opinion but that looks like my vehicle when there was a problem with the airmatic system

 

When I had my GLS, it would settle after parking extended periods of time, but it never looked like that. That looks like a leak somewhere.

 

Its not normal or ok. My 2008 GL450 has been sitting for 2 weeks and the height hasn't changed at all. It did, however, sag like that when the airbags had leaks. It hasn't sagged since I replaced them.

 

Sales guy is talking rubbish. If you want the car tell them to replace the rear airbags then work out a deal (after the airbags are fixed).

 

Thanks for confirming my suspicions. I've crossed this one off the list and will most likely be pulling the trigger on a pristine '14 GL350 with only about 40k on the odo. Doing final checks today so hopefully it all clears.

 

Hope you know what you are getting into with the diesel.

 

I do. The recent Canadian settlement with MB gives me some additional comfort as well. Fingers crossed I don't run into some of the same horror stories found on the forums here.

 

MB's are incredibly consistent and that's why I've been an MB owner for more than two decades. If you are not an early adopter, you can save yourself a lot of heartache by avoiding the problematic models, engines, and options.

 

mine used to do this with the oem rear air suspension. I swapped them out with arnotts and their lifetime warranty and havent had any sagging since. Still same ride quality and theyre surprisingly easy to change. loosen the air line nut and spin off the bag.

 

Is this a DIY? Can you post the steps?

 

I just found this post searching the internet. Our car just has the same problem I think. How much was the repair from the dealership if I may ask? Thanks.

 

It takes around 15 minutes per side to do the job if you've never done it. Search Youtube for videos.

 

I just traded in a 2018 GLS. I bought it new. It never sagged, even when parked for a days, until just this year. I am sure it had a leak.

 

Hello, new to the board. Just purchased a 18 w that exact sag, how much is it to fix?

 

I did the compressor myself on ours....EASY fix. You do not need to be too awful mechanically inclined to do it (you have to be able to take off a tire, PS front)....what happens, the bags sag, the pump burns out....

https://www.fcpeuro.com/products/sus...t-166320010480


All in all, about 30 min to swap them out.

 

In hind sight, was there a warning that you missed? Something I should be watching for? If it was sagging while parked, was it noticeable when it lifted back up? Why does it always seem to be the back? So many questions...

 

For us, we got a warning light that said "Air pump over heating" (or something similar). I saw it first when I was raising the car to change the oil (I assume yours has the same lift ours has). We had a slight leak in the pass side air line, a pin hole in the pipe that was super easy to just replace.

 

I guess I'll never catch it! I use a suction tank...

 

Definitely a leaking air spring; probably the passenger side. AutohausAZ.com has the Arnotts, RockAuto.com has the Bilsteins (these are what I purchased), and FCPEuro.com has the OE Mercedes air springs.

My GLS allows you to raise the car for ground clearance (maybe all the Mercedes SUVs have this) which I do when I change the oil. I noticed that every time after changing the oil and lowering the car to the normal ride height it would be sagging the following morning. Start the car and the air pump and leveling system would reset the car to the correct ride height. I had my car in to an independent shop to replace a bad passenger side rear wheel bearing and I had them install the Bilsteins while they had the rear hub assemblies off which they did for an additional $300, but they were right in your face while doing the wheel bearings.

There are some fairly good YouTube videos about how to do it.

 

Takes too long to please me....for some reason watching the oil drain is cathartic for me.

 

The trick is getting the temperature just right! (Ask Goldilocks!)

Too cold and it takes forever, too hot and the tube collapses.

Just right and it's done by the time you finish changing the filter.