2013 — 2016
2.1L (OM651) - E220 BlueTEC
Diesel
Perform a 'cold-start' listener test: Ask the seller not to start the car before you arrive. Listen for a short rattle from the engine bay, which may indicate the timing chain tensioner or cam adjusters beginning to show their age.
Test the 7G-Tronic transmission: During a gentle acceleration run, observe if the gear changes are smooth. Any hesitation or 'clunking' between 2nd and 3rd gear might suggest the transmission fluid/filter service is overdue or that the conductor plate requires attention.
Inspect the AdBlue system: Check for any warning messages on the dash regarding the 'AdBlue' or 'SCR' system. These systems can sometimes trigger sensors faults in higher-mileage examples of this era.
Check the panoramic roof (if fitted): Operate the sliding roof fully to ensure it moves without noise or stuttering, as the tracks on these models benefit from periodic lubrication to avoid binding.
Usually marks the point where the original suspension bushings and engine mounts might start to feel less compliant.
Often a time to verify if the alternator pulley and water pump have been inspected or refreshed to maintain cooling efficiency.
The stage where you may want to ensure the DPF (Diesel Particulate Filter) has been monitored for ash accumulation and that the injectors have been checked for spray pattern consistency.
Prioritize a vehicle that comes with a documented history showing transmission fluid service every 60,000 to 80,000km.
Verify that the engine oil has been changed using the specific Mercedes-approved low-ash oil required for the OM651 engine.
Inspect the tyre condition; these vehicles are heavy, so uneven wear often points to alignment needs rather than major faults.
Check the coolant condition; ensuring it is clean and at the correct concentration helps protect the longevity of the heating system.
Keep a consistent eye on the AdBlue levels, ensuring you use a high-quality fluid to keep the selective catalytic reduction system happy.
Estimated repair costs if issues arise
While the OM651 is robust, the timing chain is a wear item. If the engine develops a distinct rattle, it is wise to budget for a preventative replacement to ensure long-term peace of mind.
If the service history is missing this, it is highly recommended to perform it soon after purchase. This includes a new filter, gasket, and high-spec transmission fluid.
These cars are known for their comfort, and if you notice a slight vibration at idle, the hydraulic engine mounts may have collapsed over time.
If your car features air suspension, the airbags can eventually lose their seal. It is helpful to set aside a buffer should a strut require replacement in the future.
Noticed something inaccurate or missing?Suggest an edit→
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