Audi A4 Free Workshop and Repair Manuals Audi A4. The Audi A4 is a compact executive car produced by Audi since 1994 to date. There are four generations of the car produced based on the Volkswagen B platform. The first of the A4 generations succeeded the Audi 80. Its treated as a continuation of the Audi 80 lineage by the auto maker Audi. 2001 Audi A4 Quattro Crankcase Breather Hose | Advance Compare 2001 Audi A4 Quattro Crankcase Breather Hose brands. Check prices & reviews on aftermarket & stock parts for your 2001 A4 Quattro Crankcase Breather Hose. Order your parts online or pick them up in-store at your local Advance Auto Parts.