Hi. I've got a 2011 GL450 with Airmatic semi-active code 489. We've had a periodic "malfunction" warning for a while and a specialist said it was ok for a bit as it wasn't sinking when turned off. In the past few weeks I have heard the compressor working harder and, the other day, on a 700 mile round trip it was extremely bumpy, suspension was down and never came out and I couldn't hear the compressor. The suspension has always been level. Questions:
1) Do I just replace the compressor & relay and see if it temporarily solves the issue?
2) Have the dealership do a full diagnostic and just replace everything (*guessing $3K?)?
3) Find a conversion kit and have my independent shop do a conversion (any idea where and how much a conversion kit is?)?
We are leaving on another trip that will be about 2500 miles over 2 weeks on the 16th.

 

There isn't all that much to the Airmatic system. However, it can be difficult to infer what is wrong with someone's system just by symptoms described in a post.

Here is what I would do. Change the compressor and then do a soapy water test at raised height, looking for stoner spit on the air bags.

It is also possible the valve block has corroded solenoid valves from the compressor pushing water droplets in. The suspension should not have sagged on your recent trip unless the bags or the valve block was leaking. More likely the former.

Leaking bags tend to bring the whole rest of the system - compressor and then valve block - down with them.

Coil spring conversion is only for the brave of heart. No one, to my knowledge, has found a known good set of springs. In theory it should be easy but theory and reality often clash.

 

First question, how handy are you with a wrench?

If you are, then these repairs are quite straight forward. Just basic removing and replacing parts, no special tools needed.
First place Id check is the intake tube on the compressor. See if its collapsed. This will cauce the compressor to fail as well

 

If your car does NOT sag overnight, it’s the compressor going out, I’m sure it is loud now.

Change the compressor if you are getting a malfunction error on the dash, like compressor is cooling down is one of the most common one.
Change it along with a new relay as well as a new intake filter.
Filter is cheap, $5 or last time I bought one.
You can also upgrade the old rubber hose between the filter and the compressor.
I’ve done it at my last compressor failure about a couple months ago.

Once this hose breaks down, compressor starts to suck dust and moisture and that’s pretty much the end of it. At first you’d notice the sound of the compressor would change then it would run all the time and then the infamous error message on the dash

Never judge the filter by its look, mine looked decent but once I split it in half, it was disgusting.

I’ll try to find some pics for you if you’re not familiar with the compressor setup.

 

Here is the air suction hose I’m talking about. Clamp is still there but hose was destroyed and disconnected.

 

And I found the picture of the new filter.

 

When you do the soapy water test, my experience was to find a leak successfully, you need to:

Inflate bags and raise to highest level
Make sure weight of the car is on the tyres as it would normally be. You need the weight of the car to pressure up the system to recreate the leak sometimes.
Dont get under the car. A bag that bursts will cause the car to fall and will kill you.
Spray all components multiple times and then wait. Leakes can hide and you only want to do this once. Dont be fooled by stopping when you find the first one. You may have multiple leaks.

And as other have said all of this is DIY. If you're replacing the front bags, consider the age and functionality of the shocks. Might be better to replace the whole units of needed.
Good luck

 

The only reason to replace only the front air bags, and not the whole strut, would be if one of the bags suffered physical damage in its early life. Generally when the bag has failed from wear, the shock absorber inside the strut could use replacement anyway, so usually the whole strut is replaced.

 

dealer cost for two front struts: $4200 in 2014
dealer quote for two rear bags: $2000 in 2014
current price could probably be higher.

for DIY:
arnott front strut: $414 each
arnott rear bag: $160 each
arnott compressor and manifold: $680

 

It’s important to understand that Airmatic does not fail.

Rather, understand that the rubber air springs are simply periodic replacement items, same as tires, wipers, serpentine belts, shock absorbers.

Most often the compressor fails because it’s been overworked attempting to inflate a leaking spring. This is user error.

With the GL, it’s fairly normal that hydraulic shock absorbers are worn out on a pretty similar time frame as the air springs. They start leaking oil.

Anticipate replacement of springs and shocks every 75k miles. This is normal … and it’s expensive. It’s a large, heavy luxury vehicle with an expensive, high performing suspension system not found on less expensive vehicles, and the replacement parts prices reflect the fact it’s an expensive vehicle with unique heavy duty imported parts. This is simply cost of ownership.

 

You do 4;

replace both leaky airbags
replace both front about to pop Struts
replace compressor.

it is burned out from trying to pressurize the earths atmosphere via a leaking air bag for too long.

However, much it will cost you is entirely dependent upon how handy you are. This is not rocket surgery and can be done for around 13 1400 bucks DIY.

The dealer is going to charge more than your car is worth in repairs.

 

I have 230 K on my original ADS shocks… Living very dangerously, but still comfortably.

 

This is insulting excuse-making. The root cause is not "user error". Nowhere in the owner's manual does it list air spring replacement on a 60k interval.
The criminality of this omission is aggravated by the lack of information coming from the vehicle computers; which could easily analyze the pump duty cycle and diagnose a potential leaking spring.

P.S. "Unique heavy duty imported parts" My sides!

 

Wait, by "shocks" do you mean your front air springs?!?

 

Whelp my 2015 GL350 is giving me an intermittent suspension error, as well as “compressor cooling” when I raise it. It will not lose any height or sag when parked even for close to 48 hours and will still raise but with a few cooling periods.

The springs seem to hold their air even when parked for a while. Car still rides comfortably without issue, so the symptoms primarily point to compressor or valve block issue.

Fortunately I have extended warranty and I have made a service appointment, so I will post back afterwards.

 

No, the actual shocks.
I replaced the air springs around them about two years ago.

 

Far out. Was that difficult?

If the ride is not causing you motion sickness, and the tires are not cupping, the shocks are okay.

 

yeah, it’s a advance DIY job.
It would be for easier just to swap the whole strut assembly but man at like two grand piece or whatever no.

Tires aren’t cupping, there is a marked difference in sport mode, and there are no signs of leaks, so I’m gonna roll these until the wheels come off again.

 

Knowing what I know now I should have chucked the whole air suspension and converted to regular suspension using StrutMasters kit.

I wished the car was made to be drivable should the bags fail.

 

Depends on who you ask (this is not me/just spotted in the wild)

 

Not everyone drives on smooth asphalt. Some of us are in Nigeria.

Look at this video of my actual road.

https://x.com/princesomorin/status/1...lTuqWYxu6nKJGg

 

Yeowch. That $300 bag is causing $3000 plus worth of damage right there.

should have changed it before it got to this point.

 

That looks like my GL. If that's NJ that could have been my wife driving. The last time the compressor went out all the corners were doing wacky things.

 

Thank goodness for extended warranty.

 

Thats crazy! That filter at a local parts store would be about $25

Was there LABOUR on top of all that??