From the text book
Engine number
(VRL005319; Edition 11.2012)
The engine number (“code letters” and “serial number”) can be found on the left on the joint between engine and gearbox.
The engine code is also stamped on the right side of the cylinder head and on the cylinder block.
The engine number consists of up to nine characters (alphanumeric). The first part (maximum 3 characters) makes up the “engine code”, and the second part (6 characters), the “serial number”. If more than 999,999 engines were produced with the same code letters, the first of the six digits is replaced by a letter.
In addition, there is a sticker on the toothed belt guard with “engine code” and “serial number”.
The engine code is also included on the vehicle data sticker.
Vehicles with four digit engine codes
Starting with the letter “C”, new four digit engine codes have been introduced. The first 3 digits denote the mechanical design of the engine and are stamped on the engine as before. The fourth digit denotes the performance and torque rating of the engine and depends on the engine control unit. The four-digit engine code can be found on the identification plate, the vehicle data sticker and the engine control unit.