1.8L Turbo (A4 - Engine Code AMB)

The engine number ("Engine code" and "Serial number") can be found on the rear left of the cylinder block. See Fig 1 . Additionally there is a sticker on the timing belt guard giving the "Engine code" and the "Serial number." The engine code is also given on the vehicle data sticker

Fig 1: Locating Engine Code & Serial Number - A4 (1.8L Turbo, Engine Code AMB)

Courtesy of AUDI OF AMERICA, INC.