Chevy Duramax Problems by Year – 6.6L Diesel Reliability Guide
The Chevy 6.6L Duramax diesel offers strong towing power across generations, yet certain duramax problems vary by year. Early LB7 models face injector failures from heat exposure, while LLY engines overheat under load. LML variants often encounter CP4 fuel pump issues leading to system contamination. Later L5P versions show fewer major concerns, though water pumps and glow plugs can still require attention with proper maintenance. Overall reliability improves with regular service and quality fuel.