Audi A4 2004 3.0 diesel service and maintenance
Engine oil
Engine oil capacity: 8.2 litres (8.7 quarts)
Recommended oil type (Oil Viscosity Classification SAE) is 5W-30
Air filter
Air filter change interval is 60,000 km.
After prolonged driving in particularly dusty conditions, it is advisable to check the condition of the air filter earlier and replace it if the filter is visibly dirty.
Fuel filter
Audi A4 3.0 diesel fuel filter change interval is 30,000 km
Timing chain
Manufacturers recommended timing chain replacement interval for Audi A4 3.0 diesel is 300,000 km.
Based on real life experience, the Audi A4 2004 Avant 3.0 TDI quattro timing chain change interval is approximately 200,000 km as at this mileage it may become overstretched and require replacement, so it is recommended to check the condition of the chain periodically after this mileage is reached and replace the timing chain if it becomes excessively stretched or if unusual engine noises occur.
Engine coolant
Engine coolant (antifreeze) recommended replacement interval for Audi A4 3.0 diesel is 60,000 km or 2 years, whichever comes first.

Audi A4 2004 Avant 3.0 TDI quattro 2007 - 2008 Audi A4 2004 technical data
Audi A4 2004 owner reviews
Always consult your vehicle manufacturer's service manual for service intervals and specifications!