Vehicles using B6304F/S2 engine list:

Engine B6304F

Symptoms:
- Rough idling and hesitation during acceleration
- Engine misfires or stalling
- Oil leaks around the valve cover gasket
- Overheating or coolant loss
- Check engine light illumination

Diagnosis:
- Inspect ignition components such as spark plugs, coils, and wires for wear or damage
- Check for vacuum leaks around intake manifold and hoses
- Perform a compression test to assess cylinder health
- Examine valve cover gasket and seals for oil leaks
- Test coolant system pressure and thermostat operation
- Scan for diagnostic trouble codes (DTCs) to identify sensor or system faults

Fixes:
- Replace worn spark plugs and ignition components to restore proper firing
- Repair or replace cracked or leaking vacuum hoses to eliminate air leaks
- Replace valve cover gasket and seals to stop oil leaks
- Flush and refill coolant system; replace thermostat if faulty to prevent overheating
- Clean or replace sensors triggering check engine light, such as oxygen or MAF sensors
- Address any mechanical issues found during compression testing, such as valve or piston ring wear

Prevention:
- Follow regular maintenance schedule including timely oil and filter changes to protect engine internals
- Use quality spark plugs and ignition parts recommended for the B6304F engine
- Inspect and replace aging vacuum hoses before they crack or leak
- Monitor coolant levels and condition to avoid overheating
- Address check engine light warnings promptly to prevent further damage
- Keep the engine clean and free of oil leaks to maintain proper cooling and performance

By adhering to these diagnostic steps and maintenance practices, owners of vehicles equipped with the B6304F engine can minimize common issues and ensure reliable operation.