Vehicles using M276.956 engine list:

Engine M276.956

Symptoms:
- Rough idling or misfires
- Loss of power or hesitation during acceleration
- Engine warning light illuminated
- Excessive oil consumption or leaks
- Unusual engine noises such as ticking or knocking

Diagnosis:
- Check for fault codes using a diagnostic scanner to identify misfire or sensor-related errors
- Inspect ignition coils and spark plugs for wear or damage
- Perform a compression test to assess cylinder health
- Examine for oil leaks around valve covers and timing chain area
- Inspect the timing chain tensioner and guides for wear or failure
- Check the intake manifold and PCV system for carbon buildup or blockages

Fixes:
- Replace faulty ignition coils and worn spark plugs to resolve misfires
- Repair or replace leaking valve cover gaskets to stop oil leaks
- Clean or replace clogged intake manifold components and PCV valves to improve airflow
- Replace timing chain tensioner and guides if worn to prevent timing issues and engine noise
- Address oil consumption by repairing leaks and ensuring proper oil grade and level
- Perform regular oil and filter changes to maintain engine health

Prevention:
- Follow the manufacturer’s recommended maintenance schedule, especially oil changes every 10,000 km or 6 months
- Use high-quality synthetic oil meeting Mercedes-Benz specifications to reduce wear and deposits
- Regularly inspect ignition components and replace spark plugs at recommended intervals (typically every 100,000 km)
- Monitor for early signs of oil leaks or unusual noises and address promptly
- Avoid extended idling and aggressive driving to reduce engine stress and wear
- Keep the intake system clean to prevent carbon buildup that can affect performance

By adhering to these diagnostic steps, fixes, and preventive measures, owners of the SLK 350 (2011–2015) and SLC 350 (2015–2017) can maintain optimal performance and longevity of the M276.956 engine.