2009 — 2013
3.0L V6 Turbo Diesel (OM642) - S350 BlueTEC
Diesel
Test drive task: Gently accelerate to highway speeds while listening for any 'limp mode' behavior or lack of turbo boost. | Note: In cars of this age, it is common to consider that the variable geometry turbocharger actuator or the DPF pressure sensors may eventually show their years.
Check this by: With the car in 'Park', turn the steering wheel lock-to-lock while listening for whines or groans. | Note: The power steering pump and rack systems on the W221 are robust, but it is wise to be aware that seal degradation can occasionally occur as the kilometers climb.
Test drive task: Cycle through all suspension height settings using the 'Airmatic' switch on the center console while the vehicle is idling. | Note: The Airmatic air suspension is a highlight of the S-Class experience, though it is worth keeping in mind that the air struts and compressor can experience wear over time.
Check this by: Spend time in the cabin operating every electronic adjustment for the seats, mirrors, and infotainment. | Note: Given the complexity of the interior electronics, it is often prudent to ensure all modules are communicating well, as electrical gremlins are occasionally seen in vehicles of this vintage.
Major service point; check transmission fluid flush and air suspension compressor health.
Consider checking timing chain tensioner health and potential carbon buildup in the intake manifold.
Review condition of major suspension bushings and engine mounts for continued comfort.
Prioritize a full service history that shows regular synthetic oil changes, as the OM642 engine thrives on high-quality oil.
Ensure the transmission fluid has been serviced at least once in the last 80,000km to keep the 7G-Tronic shifting smoothly.
Keep an eye on the battery voltage; these cars are sensitive to low voltage and perform best with a healthy, high-capacity battery.
Regularly clear out the engine bay's water drainage channels to ensure no moisture pools near the cabin air intake or ECU.
Use a reputable diagnostic scanner to check for historical error codes; the S-Class records plenty of information that can tell a great story.
Estimated repair costs if issues arise
If the ride height begins to sag overnight, you might eventually need to budget for a replacement strut. We recommend looking into high-quality OEM or reputable aftermarket options.
Depending on the car's history, you might eventually need to budget for an intake manifold service if the swirl flap linkages wear out or get gunked up by carbon.
The OM642 engine is fantastic, but if this component needs attention in the future, it is a significant job requiring the removal of the turbo and intake assembly to replace the seals.
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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