2012 — 2018
4.4L (S63B44) V8 Twin-Turbo - M TwinPower Turbo high-performance
Petrol
During your test drive, find a flat, quiet stretch of road and perform a 'soft' gear shift between 2nd and 3rd. Listen for any clunking or hesitation, as the DCT gearbox can exhibit wear in the clutch packs on higher-mileage examples.
Before starting the engine, check the service history for recent 'Coolant Expansion Tank' replacements. While driving, monitor the iDrive temperature gauge closely; these V8s run hot and aging plastic cooling components are known to become brittle over time.
Ensure the vehicle is cold before you start it. Listen for any prolonged ticking or rattling from the engine bay upon startup, which could be an early indication of timing chain stretch or Vanos unit wear common in the S63 engine architecture.
Operate every single adjustment on the M-Multifunction seats. These are complex pieces of engineering, and it is common for the active bolster motors or lumbar support pumps to seize up if not used regularly.
Usually marks the time to consider fresh spark plugs and ignition coils, which are vital for maintaining the twin-turbo V8's performance.
Often the threshold where engine mounts may begin to soften, potentially leading to increased vibrations at idle.
The typical window for inspecting the suspension bushings and arms, as the weight of the M6 puts significant pressure on the front-end components.
Prioritize oil changes every 7,500km rather than the long-life intervals to keep the turbochargers happy.
Keep a close eye on the charge air cooler coolant level, as these systems must remain topped up to prevent heat soak.
Ensure the iDrive system is updated and checked for any stored 'shadow codes' that don't trigger a dashboard light.
Regularly inspect the tyre tread depth, as the high torque of the S63 engine can make short work of rear rubber.
Verify the brake fluid has been flushed every two years to maintain the stopping power required for a vehicle of this performance class.
Estimated repair costs if issues arise
Given the heat cycles of this engine, the rubber lines surrounding the turbos can occasionally weep. It is worth keeping a small reserve in your budget for potential cooling system refreshes.
While the dual-clutch transmission is incredibly fast, it is a complex component. If you notice slippage in higher gears, you might eventually need to budget for a specialized shop to perform a clutch service.
To keep that precise M-handling feeling, you might eventually need to budget for refreshing the front control arms and thrust arm bushings as the rubber ages.
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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