Replacing BMW E46 320d (M47D20) expansion tank and thermostat - preventive maintenance

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Replacing BMW E46 320d (M47D20) expansion tank and thermostat - preventive maintenance

Parts needed:

• Expansion tank (part number: 17117573781)
• Thermostat (part number: 11517787113)
• Coolant (BMW-approved)
• Various hose clamps

Replacement procedure:

• Drain cooling system
• Remove old expansion tank and thermostat
• Install new thermostat with fresh O-ring
• Install new expansion tank
• Refill cooling system with proper coolant mix
• Bleed cooling system thoroughly
• Check for leaks and proper operation

Preventive tips:

• Replace these components every 60,000-80,000 miles
• Inspect cooling system regularly for signs of wear or leaks
• Use only BMW-approved coolant

Note: Proper bleeding of the cooling system is crucial to prevent overheating issues.