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.

Go with either 2 or 3. You will eventually need to replace all four struts and compressor so you can piece meal it or replace it all at same time. Long term springs have worked well for many years. Do a search on Arnott suspension web site.

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Jim

The airmatic on these are actually pretty simple. Have someone who has the capability to plug in and manually add and remove air from each corner and read pressure and level values. Figure out which corner is losing air. Replacing the compressor is always a good idea when it has been working overtime due to a leak. The compressor always loses the battle.

I just recently purchased the GL and the front air struts were replaced April 2017 at 84k miles with Arnott brand from the local dealer. They came with a lifetime warranty. Unfortunately the warrant is not transferrable to me. Anyway, I'll be replacing the front ones this week. The vehicle is currently at 197k miles and the front drops. During certain times I can feel and hear the leak from the drivers front unit.

I did not find an Arnott manufactured spring conversion kit for it.

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Jim

The air springs with Airmatic are simply limited life items, same as tires, wiper blades, serpentine belts.

The fact they eventually leak is not a failure, it's simply a fact of life.

So many people want to look first at other system components which are much less likely to fail. If it leaks once, what's with "wait and see?"

All cars have both springs and shock absorbers. At GL front the two are combined into a single unit called a strut. At rear, they are separate items.

It's my experience shock absorbers have about the same life as Airmatic springs. My rear shocks were putting oil on the ground about the same time my rear springs were collapsing.

It's expensive, but the intelligent approach is to renew the entire suspension at the same time. Front struts, rear springs, rear shocks.

If you do allow the compressor to continue to attempt to inflate the universe, you will soon require a new compressor. These are not cheap either.

Discussion: there is much psychological anxiety regarding Mercedes Airmatic. Mercedes are very expensive luxury cars and when new cost a lot of money. They can be a bit "flavor of the month" and when they get older they depreciate quite a bit. That means you can purchase a used one at a fairly reasonable price. It DOES NOT mean it will be a car that's cheap to run and it DOES NOT mean inevitable and required periodic renewal of the special suspension is going to be cheap. I've read somewhere the average American can't come up with $500 for an emergency. Imagine the stress when your Mercedes requires a $3000 suspension renewal.

So, often under this financial stress, people badmouth Mercedes and the Airmatic system and sometimes make the ridiculous decision to convert to steel springs, severely handicapping the vehicle and imho converting its resale value to zero.

Don't get stars in your eyes!

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

I found the Arnott replacement air springs (both front struts, rear air springs, compressor and valve assy) cost just over $1700. Where their coil spring conversion kit (C-3547) was under $1200. There are other companies making conversion kits ranging from 500 to 1700. Suncore, Strutmaster and a slew of Chinese companies. With the conversion you need a module that will prevent the warning light from being activated. That is included with some of the higher priced kits. I stayed with the air suspension and have not regretted it. It took me about 7 hours to install all the parts and the car has
remained at the proper height ever since.

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Dave
88 300E 250K Sold
2000 C230K Totaled @104K
2003 ML320 156K Sold
2009 E350 4Matic Sport 46K Sold
2011 ML350 60K Sold
2014 GLK350 46k
2012 GL450 55K

Ford/Lincoln guy here, reluctant MB virgin. I've got lots of experience with Lincoln air suspension. The compressor is the expensive bit. If it starts running regularly replace the bags. Its easy on the Towncars/GMs because there's only air springs at one end. On these Kraut Caddies I suppose there's probably a situation where you would replace the rear bags but not the fronts or vice versa but really, if one is leaking the rest are past their best before date. Change them all at once.

I've owned more Towncars in my life than all other cars combined. I only ever gave up on one of them and swapped in the coil springs. Air suspension is great when its working but as someone else has already pointed out, the monthly depreciation on most of these cars if you buy new is in the $1-2,000 range. Don't expect them to be cheap to operate.

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R.J.(Bob) Evans
2013 ML350