2000 — 2005
2.7L I5 (OM612)
Diesel
Check for 'Black Death' injector seals | Note: Open the bonnet and look for carbon buildup/black tar around the base of the five injectors; this is a common OM612 failure.
Test transmission torque converter lock-up | Note: Watch the tachometer on the open road; fluctuating RPM at steady cruising speeds indicates a failing torque converter lock-up clutch.
Inspect SAM (Signal Acquisition Module) operation | Note: Test all windows, lights, and wipers repeatedly; moisture ingress in the fuse boxes is a known W203 electrical gremlin.
Perform a cold start check for glow plug performance | Note: A flashing glow plug light after startup usually indicates one or more faulty plugs or a failing relay module.
Expect to be deep into the 'A' or 'B' service cycle; ensure high-quality synthetic oil has been used to protect the turbo bearings.
Consider replacing the automatic transmission fluid and filter, even if the service manual claims 'sealed for life'—it is not.
Suspension fatigue is common by this stage; front lower control arms and bush replacements will be required to restore steering precision.
Perform oil and filter changes every 10,000km using MB-approved low-ash engine oil.
Inspect engine mounts for sagging, which causes excessive vibration at idle.
Clean the Mass Air Flow (MAF) sensor and check the intake hose for oil leaks.
Replace the serpentine belt and tensioner assembly to prevent cooling system pump failure.
Check the coolant condition; ensure OAT-compliant coolant is used to protect the aluminum radiator.
Estimated repair costs if issues arise
Budget for electronic repair or replacement if you notice limp mode under heavy acceleration.
Often the cause of erratic shifting; common in W203 high-mileage examples.
Necessary if the steering feels loose or 'clunky' over NZ speed bumps.
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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