Truck Engine Identification

The Detroit Diesel on-highway engines consist of the Series 60, the DD13 and the DD15. To identify a Detroit Diesel engine, locate the metallic plate on the driver's side of the valve cover. An engine serial number will be present, in addition to a model number. Detroit Diesel Series 60 engines are painted light blue from the factory, and the DD13 and the DD15 engines are painted black. Series 60 serial numbers will begin 06R followed by seven digits. The DD13 and the DD15 consist of 10 numeric digits.

Caterpillar on-highway engines consist of the 3208, the 3406 and the C series engines. All Caterpillar engines are painted yellow from the factory. Serial numbers consist of a string of alphanumeric code. The serial and model number is located on a metallic plate on the passenger side of the valve cover. If the metallic plate is missing, the engine serial number is stamped on the passenger side of the cylinder block, just behind the exhaust manifold.

Cummins on-highway engines consist of the N14 and M11, and the ISX, ISL and the ISM. Cummins engines are painted red from the factory. The engine and model numbers are engraved on a metallic plate located on the driver's side front cover. All Cummins serial numbers are eight numeric digits. If the identification plate is missing, the engine serial number is stamped on the passenger side of the cylinder block, near the rear of the engine.

Navistar on-highway engines consist of the DT series. The DT series are painted black from the factory. The engine serial number is located on a metallic plate on the driver's side of the cylinder block at the center of the engine and just below the cylinder head. The serial number will consist of 13 numeric digits. If the plate is missing, the owner will need to find the fuel pump and turbo part numbers located on each part and call their local Navistar dealer to determine the engine type.

Many truck manufacturers used the same model engines in their on-highway vehicles. During the 1980s and 1990s, Detroit Diesel, Caterpillar and Cummins built engines for most of the truck manufacturers in the United States. A Freightliner, Peterbilt or a Navistar may have been built with a Detroit Diesel, Caterpillar or Cummins engine up until the late 1990s. Beginning in the early 2000s, however, engine companies began to produce engines for specific truck manufacturers. Detroit Diesel engines are now used exclusively in Freightliner trucks. Caterpillar and Cummins engines are used by Peterbilt, Kenworth and Freightliner. Navistar engines are still proprietary to International Harvester Trucks.

Throughout an engine's life, there is a chance that the engine was repaired or overhauled at some point. As most engine serial numbers used to identify the engine are located on metallic plates; these plates to wear and in some cases become illegible. In other cases, parts such as the valve cover are changed without the repair shop removing the old identification plate and installing it on the new one. It is good practice to locate the serial number that is stamped on the cylinder block to prevent misidentification of the engine.