If your truck runs with these engines, you'll travel 1 million miles. Caterpillar C15 engine is a legend. Released in 1999, this 14.6 liter power plant was designed with a lifespan of 1 million miles with proper maintenance, and many of them reached well over that golden mark. Detroit's DD15 was released in 2007 and offers less complexity to achieve maximum durability. While that sounds like a usual commercial statement, many 15s out there already reached the 1 million mile milestone. Take good care of a Cummins N14 red top and it will take care of you. You can reach 1 million miles with this guy and only be halfway through the engine's life. Tons of units have reportedly survived well over 2 million miles.