Few engines achieve legendary status like the Cummins B-Series diesel. It has powered Dodge (and later, Ram) pickup trucks for decades, and the 5.9-liter inline-six featured in this recent I Do Cars video had a tough life. It came from a 2006 Dodge Ram 2500 used by a roofer, and at 368,000 miles, it wasn't running very well. But it was running. Given the wear and tear on this engine, that's quite remarkable.
To be honest, 368,000 miles isn't that much for a diesel, but it seems the owner didn't prioritize maintenance. The video starts with a description of the truck being in a terrible condition, both inside and out. It was used for work, and when the owner finally brought it to the shop for engine issues, the entire truck was deemed too damaged to justify the repair cost.
There isn't much to see in the first half of the teardown. The top end of the engine looks decent considering its age and mileage. The first signs of trouble appear once the head is removed, revealing the pistons and upper block. Several cylinders have deep grooves in the walls, and bits of debris are found in the combustion chambers beneath the head. Something inside the engine had clearly broken.
As the pistons are removed, we see multiple broken parts. Piston rings on three of the six pistons were snapped, making those cylinders effectively useless. The damaged rings scored the cylinder walls, which in turn scored the pistons. Heavy wear was also found on the camshaft lobes, rod bearings, and tappets. At the very least, this engine would need reboring and a new bottom end to run again, properly.
Even with three broken rings and metal fragments inside, the Cummins fought to the end. What caused the damage? The video suggests a general lack of maintenance as the likely cause. This could include infrequent oil changes, using low-quality oil, or ignoring smaller issues until they became larger ones. In any case, this engine has towed its last trailer. The cumulative problems are too extensive to justify a rebuild.
