Exact replacements for Cummins Oil coolers and other Cummins engine cooling devices are sold by Mr. Cool internationally. Cummins is a diesel engine manufacturer providing both marine and industrial engines with superb quality and reliability. Cummins Marine Diesel, a joint agreement with Mercruiser, provided small diesel engines for the marine market since around year 2000. The only difference you'll see with our replacement Cummins Oil coolers is the price.