Shop Owner Points Out the Biggest Weakness He’s Found in Duramax Engines
David Bell runs Dave’s Auto Center in Centerville, Utah. For over 30 years, his team has maintained, repaired, and rebuilt all manner of cars. Thanks to his clear, helpful explainer clips, he’s built a decent social media following. He’s taken to the camera multiple times to share the biggest weakness he’s found with a popular Duramax diesel engine.
Certain GM Duramax engine assemblies, particularly the 2001-2016 6.6L in HD Sierra and Silverado pickups, have a tiny weak point that can lead to catastrophic engine damage.
In GM’s design, the crankshaft nose uses a set of dowel pins. One holds the harmonic balancer in place, and the other drives the oil pump gear. Unfortunately, the pins have a tendency to shear off. Once this happens on the back position pin, the crankshaft stops driving oil pressure. This starves the engine of oil and causes costly damage.
A sheared-off front position pin can cause the balancer to spin or go off-kilter, resulting in abnormal vibration levels the engine isn’t designed to withstand.
The solution is pretty straightforward, and 2001-2016 6.6L Duramax owners can even have this procedure done preventatively before catastrophic damage happens.
Dave’s shop installs a long, horizontal keyway on the crankshaft nose to replace the shear-prone dowels.
Importantly, if truck owners have suffered engine damage and are paying for repairs, they should ensure the pin design is addressed so this problem doesn’t just happen again.
