Through a paper, http://www.syntheticwarehouse.com/Specsheets/audi_engine_sludge_v4.pdf “Based on this information provided by VW/Audi of America, the use of AMSOIL AFL, 5W-40 Synthetic European Engine Oil satisfies the lubricant requirements for extended warranty coverage as it is formulated to meet and exceed the VW 502.00 performance specification. AMSOIL AFL is recommended to be changed at the extended drain intervals established by the European car manufactures. According to VW/Audi (2), this interval is 10,000 miles, or one year, whichever comes first.” Through the mobil website, Oil Recommendation for Audi A4 FOR AUDI A4 1.8, 1781cm³ Eng. MOBIL RECOMMENDS