How to Read Mercedes Engine ID Numbers

1. Open the hood of your Mercedes. Locate the stamped engine ID number on the top or side of the engine block, towards the rear of the engine.
2. Write down the letter or letters that begin the engine ID number. These letters indicate the style of motor (sedan, touring, roadster and so on) installed. See the chart listed in the resources below for a comprehensive definition of the letters and their meaning.
3. Write down the first three numbers. The first three numbers correspond to the type of engine that you have (diesel, oil and such). For example, an M116 type engine would have an engine ID number that begins with '116' and an M114 type engine would begin with '114.'
4. Write down the next three numbers making sure to leave a space between this set and the first set you wrote down. This set of numbers indicates what version of motor it is (i.e. 2.2 lt, 2.3, 6 cyl, 8 cyl and so on). One type of motor may have many different possible versions.
5. Skip a space and write down the next two numbers. These two numbers will tell you where the engine was installed, what side driving it was for (left or right) and the type of transmission associated with it. After 1983, the second number in this set was replaced with a letter. A series of letters (like A,B,C,D,E) was assigned to each factory. For a partial list of the assignations of these numbers, see the charts listed in the resources below.
6. Write down the remaining set of numbers. This is the specific serial number of your engine.