2010 — 2014
4.7L (M278) - CL 500 Bi-Turbo facelift
Petrol
Listen carefully for a rattle during a cold start; this can be an indication that the cam chain tensioners or adjusters might be due for inspection to ensure the M278 engine runs optimally.
While driving in stop-start traffic, pay close attention to the gear changes; any harshness might suggest that the 7G-Tronic transmission could benefit from a software update or a fluid service.
Cycling through all the buttons on the COMAND infotainment screen and air suspension controls; electronics in these models are complex, and you want to ensure all modules are communicating without error messages.
During your highway portion of the drive, feel for any vibration through the steering wheel at speed; this is often a simple sign that the suspension bushings or engine mounts are reaching an age where they may prefer replacement.
Consider a full transmission fluid and filter flush to maintain shifting smoothness.
Inspect the ABC (Active Body Control) suspension lines and hydraulic fluid for signs of aging.
Monitor for any signs of turbo-related cooling system wear, common in high-performance bi-turbo setups.
Prioritise regular engine oil changes using high-quality synthetic oil every 10,000km to protect those twin turbos.
Keep an eye on the coolant levels; the M278 engine performs best when the cooling system is kept in top-tier condition.
Ensure the cabin air filters are replaced annually to keep the climate control system operating cleanly.
Check the condition of the brake rotors and pads regularly, as the weight of the CL 500 can be demanding on these consumables.
Ask the previous owner for records of the spark plug service, as these should be replaced precisely to maintain engine efficiency.
Estimated repair costs if issues arise
The Active Body Control is a highlight of the CL experience, but it involves high-pressure hydraulics. If this component needs attention in the future, the estimated cost in NZ is reflective of the specialized labour and genuine hydraulic components required.
As part of long-term care for the M278 engine, you might eventually need to budget for a preventative inspection or replacement of the timing chain components to ensure longevity.
These rubber components take a lot of torque. Depending on the car's history and driving style, you might eventually need to budget for replacing these to maintain that signature Mercedes-Benz refinement.
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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