Duramax V8 engine

The Duramax is a General Motors diesel engine family for light to medium duty trucks, designed by GM and Isuzu. The 6.6-liter Duramax is produced by DMAX, a joint venture between GM and Isuzu in Moraine, Ohio. The Duramax block and heads are poured at The Defiance GM Powertrain foundry in Defiance, Ohio. This engine was initially installed in 2001 model year Chevy and GMC trucks and has been an option since then in pickups, vans, and medium-duty trucks. In 2006, production at Moraine was reportedly limited to approximately 200,000 engines per year. On May 9, 2007, DMAX announced the production of the 1,000,000th Duramax V-8 diesel at its Moraine facility.

Engine RPO Codes

LB7

RPO LB7 (engine code "1") was first introduced in 2001 and continued until mid-2004. It is a 32-valve design with high-pressure common-rail direct injection and an experimental composite design cylinder head. The most common issue with the LB7 is injector failure, so common that a special policy bulletin was issued (#04039B). Fuel leaked and entered the crankcase, causing oil dilution. Early on, customers came forward complaining of severe overheating, and in some situations, blown head gaskets. Initially GM denied it was a problem, but after being sued by a consumer group, GM relented and included overheating and blown head gaskets as a warranted item. GM issued a warranty for this after the fact for injectors, which now have 7 year/200,000 mile coverage. The following trucks use the LB7: