Vehicles using OM642.873 engine list:

Engine OM642.873

Symptoms:
- Rough idling and loss of power
- Excessive smoke from the exhaust, often black or blue
- Engine warning light illumination
- Increased oil consumption or oil leaks
- Unusual noises such as knocking or ticking

Diagnosis:
- Check for turbocharger faults, as the turbo is a common failure point
- Inspect the EGR (Exhaust Gas Recirculation) valve for clogging or malfunction
- Perform a compression test to assess cylinder health
- Scan for fault codes related to fuel injectors and sensors
- Examine the timing chain and tensioners for wear or elongation
- Inspect for oil leaks around the valve cover gasket and oil cooler

Fixes:
- Clean or replace the EGR valve to restore proper exhaust flow and reduce smoke
- Replace faulty turbochargers or repair turbo components if damaged
- Renew fuel injectors if misfiring or leaking is detected
- Replace timing chain and tensioners to prevent engine damage and noise
- Repair or replace leaking gaskets and seals to prevent oil loss
- Regular oil and filter changes using manufacturer-recommended specifications to maintain engine health

Prevention:
- Adhere strictly to scheduled maintenance intervals, especially oil and filter changes
- Use high-quality diesel fuel and additives to keep injectors and combustion chambers clean
- Avoid prolonged idling and aggressive driving to reduce stress on the turbo and EGR system
- Periodically inspect and clean the EGR system to prevent clogging
- Monitor oil levels regularly and address leaks promptly to avoid engine damage
- Ensure software updates are applied to optimize engine management and emissions control systems

By following these diagnostic steps and maintenance practices, owners of Mercedes Benz GLC 350 d 4MATIC (2018–2019) and Coupé models with the OM642.873 engine can mitigate common issues and maintain reliable performance.