GM Duramax engine
| Duramax Diesel engine | |
|---|---|
| Overview | |
| Manufacturer | DMAX |
| Production | 2001 – present; |
| Chronology | |
| Predecessor | 6.2 and 6.5 L Detroit Diesel |
The Duramax is a General Motors diesel engine family for 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.
RPO LB7 (engine code "1") was first introduced in 2001 and continued until early-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:
500 lb-ft @ 1,600 rpm 2004 LB7: 300 hp @ 3,100 rpm LLY: 310 hp @ 3,000 rpm LB7: 520 lb-ft @ 1,800 rpm LLY: 520 lb-ft @ 1,600 rpm The LLY was introduced in 2004 and replaced the LB7 completely mid-year
The LLY (internally called the 8GF1) (engine code "2") is a 6,599 cc (402.7 cu in) turbocharged engine which debuted in mid-2004 and continued until the end of 2005. It is a 32-valve design with high-pressure common-rail direct injection and aluminum cylinder heads. The LLY was GM's first attempt to implement emissions requirements on their diesel trucks. To meet this goal they turned to a newly developed Garrett turbocharger with a variable geometry vane system and they installed an Exhaust Gas Recirculation valve or (EGR Valve). Learning from problems with injectors in the previous LB7 GM changed the valve covers to allow access to the injectors without having to remove the valve covers, saving significant labor costs if injector replacement became necessary.
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