What are the most common Mercedes-Benz GLS problems?
According to Au7o's analysis of 2,600+ owner reports, the 2018 Mercedes-Benz GLS has 4 documented issues. The most frequently reported are: AIRMATIC Air Suspension Failure, 9G-Tronic Harsh Shift, OM642 3.0 V6 Diesel Oil Cooler Seal Failure Leaking Oil into the Engine Valley (GLS 350d). Of these, 1 is rated critical and should be addressed promptly.
Is the Mercedes-Benz GLS reliable?
The 2018 Mercedes-Benz GLS has 4 known issues documented across 2,600+ owner reports. 1 issue is rated critical: AIRMATIC Air Suspension Failure. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
How much does it cost to fix common Mercedes-Benz GLS problems?
Repair costs for known Mercedes-Benz GLS issues range from $150 to $4,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, AIRMATIC Air Suspension Failure, typically costs $800-$4,000 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 2017-2023 Mercedes-Benz GLS AIRMATIC Air Suspension Failure?
The GLS AIRMATIC system is prone to air spring leaks and compressor failure due to the vehicle's heavy curb weight (5,700+ lbs). Front air springs tend to fail first. The compressor overworks to maintain ride height and eventually burns out. Repairs typically run $800-$4,000. Severity: high.
What is the 2017-2023 Mercedes-Benz GLS 9G-Tronic Harsh Shift?
The 9G-Tronic nine-speed automatic exhibits harsh low-speed shifts and hunting between gears on inclines. The transmission software struggles to select the optimal gear among nine ratios, particularly noticeable in stop-and-go traffic. Repairs typically run $150-$2,500. Severity: medium.
What is the 2017-2019 Mercedes-Benz GLS OM642 3.0 V6 Diesel Oil Cooler Seal Failure Leaking Oil into the Engine Valley (GLS 350d)?
The 2017-2019 X166 GLS 350d uses the OM642 V6 turbodiesel, not the OM656 inline-six fitted to the X167, and it inherits the OM642's signature fault: the two seals on the engine-oil cooler that sits at the bottom of the V between the cylinder banks harden from heat and leak. Merce… Repairs typically run $1,500-$4,000. Severity: medium.
What is the 2017-2019 Mercedes-Benz GLS M276 / M278 / M157 Camshaft Adjuster Solenoid and Cam Sensor Oil Leak Wicking into Engine Wiring Harness?
The gasoline X166 GLS engines - M276 3.0 biturbo V6 (GLS 450), M278 4.7 biturbo V8 (GLS 550) and M157 5.5 biturbo V8 (AMG GLS 63) - share a well-documented failure where the seals inside the camshaft adjuster magnets (solenoids) and camshaft position sensors give up and pressuriz… Repairs typically run $250-$4,500. Severity: medium.
