MajorCommonSuspension

Mercedes-Benz GLS: X166 Airmatic Front Air Strut Leak, Valve Block and Compressor Failure

X166 Airmatic Front Air Strut Leak, Valve Block and Compressor Failure is a common suspension fault on the Mercedes-Benz GLS on the 2013–2019 cars, and we rate it major. Putting it right costs $900 to $5,500 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 10 documented faults on the Mercedes-Benz GLS.

Vehicle: Mercedes-Benz GLS
Years: 2013–2019
System: Suspension

This page covers the Mercedes-Benz GLS as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Mercedes-Benz GLS faults10 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Air suspension strut or Shock absorber / strut yet. We would rather show none than show a picture of a different part.

What goes wrong

Airmatic air suspension is standard on the X166 GL and GLS, and it continues the weak points of the earlier X164: the front air struts (which sit near engine heat) crack and leak, the rear air springs perish, and the compressor wears out from running to make up for leaks. On the X166 a sticking valve block can also stop one corner rising or lowering and is often mistaken for a failed strut. The car's weight (around 2.5 tonnes) makes these parts work hard. A leaking corner sags overnight, and a compressor that runs constantly will burn out, leaving the car sitting low on its bump stops.

What you would notice

One corner or the whole car sitting low after being parked overnight
'AIRMATIC visit workshop' or 'Vehicle too low' message
Compressor running for a long time or loudly after start
Harsh or bouncy ride
Car slow to rise after start-up

How to check it

Where to look. Front air struts behind the front wheels, rear air springs over the rear axle, compressor and valve block at the front of the car behind the bumper

View the car first thing in the morning before it has been started and check it sits level, comparing the gap between each tyre and the wheel arch lip. Start it and watch for any Airmatic message, and listen near the front for a compressor that keeps running. Use the ride height button to raise and lower the car and check it goes up and down evenly within a minute or so. Drive over bumps and listen for knocks or a crashing ride. Ask when struts, air springs or the compressor were last replaced. If a workshop inspection is possible: read the Airmatic control unit for codes, run the level and pressure tests with a Mercedes scan tool, leak-spray the struts and air lines, and check the valve block and compressor run time.

Parts involved: Air suspension strut, Shock absorber / strut.

What it costs to put right

$900 to $5,500 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Has the car ever been sitting low in the morning?”
“Have any air struts, air springs or the compressor been replaced, and when?”
“Has an Airmatic warning ever shown on the dash?”

Now check the Mercedes-Benz GLS you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

MBWorld GL Class (X166) forum thread 875042 'Airmatic' (GLS550 corner fault fixed by valve block)
Au7o known issues: 2017 Mercedes-Benz GLS, AIRMATIC air suspension failure
Mercedes-Benz TSB LI32.34-P-056198 'Fault message AIRMATIC or Active Curve System' (carcomplaints.com, 2017 GLS450)

Mercedes-Benz GLS buyer questions

Is x166 airmatic front air strut leak, valve block and compressor failure serious on a Mercedes-Benz GLS?

We rate it major and common on the Mercedes-Benz GLS. Airmatic air suspension is standard on the X166 GL and GLS, and it continues the weak points of the earlier X164: the front air struts (which sit near engine heat) crack and leak, the rear air springs perish, and the compressor wears out from running to make up for leaks. On the X166 a sticking valve block can also stop one corner rising or lowering and is often mistaken for a failed strut. The car's weight (around 2.5 tonnes) makes these parts work hard. A leaking corner sags overnight, and a compressor that runs constantly will burn out, leaving the car sitting low on its bump stops.

How much does it cost to fix on a Mercedes-Benz GLS?

$900 to $5,500 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Mercedes-Benz GLS years are affected?

Our research records this fault on the 2013–2019 Mercedes-Benz GLS. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.