The average lifespan of a 6.0 PowerStroke engine is typically around 200,000 to 300,000 miles, depending on various factors such as how the engine is used, how well it is maintained, and the specific model year of the engine. High mileage for the 6.0 PowerStroke is 300,000 miles. The higher the mileage on the engine, the more problems it is prone to develop.