Cummins engines have one defining trait that separates them from most competitors: They don’t hide their problems. When a Cummins engine is unhappy, it tells you—loudly, visibly, and early. That honesty is why Cummins remains one of the safest bets in the used excavator engine market. But “tough” does not mean “indestructible.” This guide breaks down how Cummins engines fail , what to inspect before buying, and how to avoid paying for someone else’s neglect. Where You’ll Find