Vehicles using M103 engine list:

Engine M103

Symptoms:
- Rough idling and misfires
- Loss of power and poor acceleration
- Excessive oil consumption or leaks
- Hard starting, especially when cold
- Engine overheating or coolant leaks
- Unusual noises such as ticking or knocking

Diagnosis:
- Inspect spark plugs and ignition components for wear or fouling
- Check fuel injectors for clogging or leakage
- Perform compression test to assess cylinder health
- Examine valve cover gasket and oil seals for leaks
- Test coolant system pressure and thermostat operation
- Listen for abnormal engine noises to identify worn components

Fixes:
- Replace worn or fouled spark plugs and ignition wires
- Clean or replace fuel injectors to restore proper fuel delivery
- Repair or replace valve cover gasket and other oil seals to stop leaks
- Overhaul or replace worn timing chain and tensioners if noisy or stretched
- Flush and refill coolant system; replace thermostat if faulty
- Address any detected mechanical issues such as worn piston rings or valves

Prevention:
- Follow regular maintenance schedule including timely oil and filter changes
- Use high-quality fuel and recommended engine oil grades
- Periodically inspect ignition and fuel systems for early signs of wear
- Maintain cooling system with regular coolant changes and checks
- Avoid prolonged idling and aggressive driving to reduce engine stress
- Address minor issues promptly to prevent escalation into major repairs