The Cummins 5.9 diesel engine is commonly found in buses, delivery vans and other heavy duty vehicles. The engine is also an optional power plant in the 3/4-ton and 1-ton versions of the 1994 to 2002 Dodge Ram pickup. Tupy S.A. and Teksid S.p.A. manufactured the 5.9 engine blocks for Cummins, and the only way to tell which company made a particular block is to locate the cast number stamped or embossed on the block. You must go underneath the vehicle to locate the cast number.

Step 1

Crawl under the front of the vehicle on the driver’s side and look up at the area of the block underneath the injector pump. You may need to use a mechanic’s hand lamp for better visibility.

Step 2

Locate the large wiring harness mounted to the block. The cast number for the Cummins 5.9 engine block will be located just below the wiring harness and above the spot where the oil pan meets the block.