2006 BMW 3 Series 330ci M54B30 (E46)

Engine identity

Oils and fluids

Service and parts data

Common and chronic problems

• Rear subframe corrosion (market and climate dependent)
• Window regulator failures
• Cooling system wear (water pump and thermostat)

First checks

• Inspect rear subframe and trailing arm bushings
• Check cooling system hoses and thermostat
• Confirm proper VANOS operation and valve cover gasket condition

Before replacing parts

• Save fault codes and freeze-frame data before clearing anything.
• Check engine oil, coolant and transmission fluid using the correct temperature and service procedure.
• Verify power, ground, connectors, hoses, leaks and live data before replacing expensive parts.

Important notes

• This model was sold in multiple markets including Europe and North America with slight variations in power ratings and transmissions.
• The M54 engine is noted for good reliability but typical age-related wear items should be checked.