2016 — 2019
3.0L V6 Turbo Diesel (OM642) - GLS 350d
Diesel
Listen carefully for any delay or 'clunk' when shifting between Reverse and Drive; this can indicate potential wear in the 9G-TRONIC transmission mounts or software calibration needs.
Cycle through the Airmatic air suspension settings while stationary and again at speed; ensure the vehicle lifts and lowers promptly without any dashboard error messages, as leaks can develop in the bags over time.
Accelerate firmly on an open road to check for any signs of 'limp mode' or hesitation, which could suggest a build-up of carbon in the intake manifold—a common quirk of the OM642 diesel engine.
Inspect the infotainment screen and climate controls thoroughly; in models of this age, ensure the COMAND system responds quickly to inputs, as intermittent electronic gremlins are occasionally seen in these sophisticated interiors.
Usually marks the point where the transmission fluid and filter service is recommended for longevity.
A common window to inspect the air suspension compressors and struts for signs of fatigue.
The typical interval where auxiliary belts and tensioners are evaluated for wear.
Always prioritize oil changes using approved Mercedes-Benz specification fluids to keep the turbochargers happy.
Keep a close eye on the DPF (Diesel Particulate Filter) health, especially if the vehicle does primarily short, city-based trips.
Ensure the AdBlue system is topped up at scheduled intervals to prevent potential starting lockouts.
Check for any signs of oil seepage around the 'V' of the engine, which is a known area where seals can naturally age.
Maintain a regular digital service history, as these complex vehicles rely heavily on proper software updates and specialist diagnostics.
Estimated repair costs if issues arise
As these components age, you might eventually need to budget for the replacement of air bags or the pump unit to maintain the signature Mercedes ride quality.
If this hasn't been done recently, it's common to consider this as a preventative measure to ensure smooth gear changes for many years to come.
In cars of this age, if you notice a check engine light, you might eventually need to budget for carbon cleaning or actuator repairs to restore peak engine efficiency.
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Disclaimer: This report is generated with the assistance of AI analysis based on verified automotive data. While we strive for 100% accuracy, enthusiasts should always conduct physical inspections and consult service records. View Full Disclaimer