2013 — 2015
3.0L V6 Turbo Diesel (OM642) - 190kW GL350 BlueTEC 4MATIC
Diesel
While stationary, cycle through all Airmatic suspension height settings to ensure the compressor lifts the vehicle smoothly without warning lights appearing on the dash.
During the test drive, gently accelerate and decelerate to check for any shuddering or hesitation, which may indicate the 7G-Tronic transmission requires an oil flush.
Check the coolant reservoir while the engine is cold; look for any oil contamination, as the OM642 engine oil cooler seals can sometimes perish over time.
Inspect the front and rear HVAC vents while the climate control is active to confirm the blend door actuators are working correctly, as replacing these can be labour-intensive.
Consider a full transmission fluid and filter service if not already documented in the service history.
Usually the window where the Airmatic suspension struts or airbags may begin to show signs of natural fatigue.
Typically when the DPF (Diesel Particulate Filter) may require a professional regeneration or deep clean depending on past driving cycles.
Verify the service history specifically for the 3.0L OM642 turbo-diesel; these engines thrive on high-quality, frequent oil changes.
Confirm the AdBlue system is functioning, as these models rely on it for emission compliance and the sensors can occasionally be sensitive.
Check the condition of the control arm bushings, as the heavy kerb weight of the GLS can lead to accelerated wear on suspension components.
Ensure all electronic safety systems and parking sensors are operational, as they are a signature part of the GL-Class experience.
Verify the presence of both keys and confirm they both communicate with the vehicle correctly to avoid future locksmith headaches.
Estimated repair costs if issues arise
If this component needs attention in the future, it is common to address either the airbags or the compressor unit to ensure the ride height remains stable. Depending on the car's history, you might eventually need to budget for these repairs to maintain the comfort Mercedes is known for.
In cars of this age, the oil cooler seals can occasionally develop minor seeps. Replacing them involves significant labour to access the unit, so it is wise to keep a reserve fund just in case you notice oil spots in the driveway.
Regular transmission maintenance is key to longevity. If you find the shifts become less crisp, planning for a full flush and filter kit is a sensible move to protect the drivetrain.
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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