Vehicles using OM642.850 engine list:

Engine OM642.850

Symptoms:
- Rough idling and loss of power
- Excessive smoke from the exhaust, especially black or blue smoke
- Engine warning light illumination
- Increased oil consumption or oil leaks
- Turbo lag or reduced boost pressure
- Difficulty starting or misfires

Diagnosis:
- Check for clogged or faulty EGR (Exhaust Gas Recirculation) valve causing poor combustion and smoke
- Inspect turbocharger for wear, shaft play, or boost leaks
- Perform compression test to detect cylinder wear or injector issues
- Scan for fault codes related to fuel injectors, glow plugs, or sensors
- Examine oil cooler and seals for leaks, as OM642 engines are prone to oil leaks
- Verify condition of intake manifold and swirl flaps for carbon buildup

Fixes:
- Clean or replace the EGR valve and associated cooler to restore proper exhaust gas recirculation
- Repair or replace the turbocharger if worn or damaged; check and fix boost leaks
- Replace faulty fuel injectors or glow plugs as indicated by diagnostics
- Repair oil leaks by replacing seals, gaskets, or oil cooler components
- Clean intake manifold and swirl flaps to prevent airflow restrictions
- Regular oil and filter changes using manufacturer-recommended specifications to maintain engine health

Prevention:
- Use high-quality diesel fuel and adhere to recommended service intervals
- Regularly inspect and clean the EGR system to prevent clogging
- Avoid extended idling to reduce soot buildup in the intake and EGR
- Monitor oil levels and quality frequently to detect leaks early
- Follow Mercedes-Benz maintenance schedules strictly, including turbocharger and injector servicing
- Employ periodic diagnostic scans to catch early signs of component wear or failure

By addressing these common issues proactively, owners of vehicles with the OM642.850 engine can maintain reliable performance and extend engine life.