Vehicles using OM651.980 engine list:

Engine OM651.980

Symptoms:
- Rough idling and loss of power
- Excessive smoke from the exhaust (black or blue)
- Engine warning light illumination
- Increased fuel consumption
- Difficulty starting or misfires

Diagnosis:
- Check for clogged or faulty diesel particulate filter (DPF), especially in SLK 250 CDI DPF models
- Inspect turbocharger for wear or boost leaks causing power loss
- Perform compression test to detect cylinder wear or injector issues
- Scan for fault codes related to fuel injection system, EGR valve, or sensors
- Examine glow plugs and wiring for proper operation

Fixes:
- Clean or replace the diesel particulate filter if clogged or damaged
- Repair or replace faulty turbocharger components and fix any boost leaks
- Replace worn fuel injectors or repair injector wiring harness as needed
- Clean or replace the EGR valve to restore proper exhaust gas recirculation
- Replace faulty glow plugs to improve cold start performance
- Regularly update engine software to latest version for improved management

Prevention:
- Use high-quality diesel fuel and adhere to recommended oil change intervals with approved lubricants
- Avoid frequent short trips that prevent DPF regeneration; drive at higher RPMs periodically to allow DPF cleaning
- Perform regular maintenance including air filter and fuel filter replacement
- Monitor engine warning lights promptly and address issues early
- Keep turbocharger and intake system clean to prevent boost leaks and maintain performance

By following these diagnostic steps and maintenance practices, owners of Mercedes Benz SLK 250 CDI and SLC 250 d models equipped with the OM651.980 engine can minimize common issues and ensure reliable engine operation.