Since 1959, all Mercedes vehicles have twelve digit engine numbers. The first three numbers indicate the type of engine; the second three numbers tell you the version of the engine; the next two numbers tell you where the chassis was made, if the vehicle is driven on the right or left side of the road and what type of transmission it has; and the final six numbers are the vehicle's serial number.
Unlock the hood by pulling the lever located between the driver's side door and the steering wheel.
Open the bonnet and locate the radiator behind the vehicle's grill.
Look on top of the radiator for a metal data plate. The data plate lists the chassis number and the engine number. The engine number will be preceded by the word "Motor-Nr."
The engine number is required if you order any engine parts for your Mercedes. Another way to find the engine number is by looking at your Mercedes' Data Card, which comes with the vehicle's original manuals.