2013 — 2020
3.0L V6 Turbo Diesel (OM642) - S350d
Diesel
While driving at low speeds, gently turn the steering wheel lock-to-lock to listen for any clicking or whining from the air suspension or power steering rack, as these can wear on heavier luxury vehicles.
Check this by idling in 'Park' and cycling through all climate control settings, ensuring that air flows correctly from all vents and the compressor engages smoothly without audible groaning.
During the test drive, gently apply the brakes at highway speeds and monitor the steering wheel for any subtle vibrations, which could indicate that the front brake rotors are beginning to warp or show wear.
Inspect the infotainment screen and digital instrument cluster for any flickering or dead pixels, as these complex electronic modules can become temperamental after several years of service.
Usually marks the point where the initial set of air struts may start to lose pressure; keep an eye on how level the car sits after being parked overnight.
A common window to perform a comprehensive transmission fluid and filter flush to ensure the 9G-TRONIC gearbox continues to shift seamlessly.
An interval where the intake manifold gaskets and associated breather hoses on the OM642 engine often require inspection for minor oil seepage.
Prioritize a pre-purchase inspection specifically with a technician familiar with Mercedes-Benz diagnostics to pull any stored fault codes.
Check the service history log to ensure the engine oil has been changed using the correct low-ash synthetic oil required for the diesel particulate filter (DPF).
Confirm the sunroof drainage channels have been cleared during past services to prevent any water ingress issues inside the cabin.
Verify that the battery health is sound, as the W222 relies heavily on a stable electrical system for its myriad of electronic safety and comfort features.
Review the history to see if the engine mounts have been addressed, as these play a huge role in maintaining the signature 'S-Class' vibration-free cabin experience.
Estimated repair costs if issues arise
If the ride height begins to struggle or a corner of the car sags, you might eventually need to budget for strut replacement. These are sophisticated components that provide the S-Class's iconic comfort.
Depending on the car's driving history—especially if it has spent a lot of time in city traffic—you might eventually need to budget for a professional DPF clean or replacement to keep emissions in check.
In cars of this age, it's common to consider that these rubber mounts can compress over time, leading to minor vibrations at idle. Replacing them restores that 'brand new' smooth feeling.
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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