Common 3.0L Duramax engine problems reported by owners

The 3.0L Duramax diesel engine, found in various GM trucks and SUVs, is reportedly experiencing common issues including extended cranking times, oil leaks, and diesel exhaust fluid system problems. Owners frequently report long start-up crank times, often attributed to faulty camshaft position exciter wheels. Oil leaks, particularly from the rear main seal, and DEF system malfunctions leading to reduced power are also significant owner complaints. These issues primarily affect the first-generation LM2 3.0 Duramax, with newer LZ0 variants not exhibiting the same long cranking problems. The engine was offered in models like the Chevrolet Silverado and GMC Sierra before being discontinued for the 2025 model year.