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Remanufactured/rebuilt engines, engine parts/rebuild kits and informational articles about car care. The "Technical Bulletins" section contain articles regarding reported problems with specific engines.
The Duramax LB7, LLY, LBZ, LMM and LML remanufactured diesel engines are available at Roadmaster Engine World.
The Duramax is a General Motors diesel engine family for light- and medium duty trucks, designed by Isuzu. The 6.6-liter Duramax is produced by DMAX, a joint venture between GM and Isuzu in Moraine, 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 mid 2004. It is a 32-valve design with high-pressure common-rail direct injection and an experimental composite design cylinder head. The most problematic issue with the LB7 is injector failure. 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:
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.
The following trucks used the LLY engine:
The 2006 LLY (engine code "2") debuted in the beginning of 2006 and ended production with the start of the 2007 calendar year. Mechanically it is identical to the LBZ and is mated to the new 6-speed Allison transmission however it retained the LLY designation.
The LBZ (engine code "D") debuted in late 2006 and continued into 2007 sold only in the "classic" body style. It has a more powerful tune loaded into the computer that allows it to produce more power and torque.
The LMM (engine code "6") debuted part way through 2007 and ended production with the start of the 2011 calendar year and is mated to the 6-speed Allison transmission. The LMM was the only Duramax offered for model years 2008-2010.
(Diesel Oxidizing Catalyst) where the fuel is burned to elevate the temperature of the exhaust. This hot exhaust flows into the DPF and burns the trapped soot.
The 6.6L RPO LML (VIN code "8") is the latest version (2011-present) of the Isuzu/GM Duramax V8 diesel engine and actually a further advanced version of the LMM engine with the majority of the changes addressing a required drastic reduction in engine emissions. Some mechanical aspects of the engine, such as piston oil flow design for improved temperature control and oil pump design, were also improved to enhance durability even further.
The LML engine was significantly updated for 2011 to provide improved exhaust emissions that comply with the new federal emission standards for diesel engines, provide better engine rigidity and further noise reduction. New 29,000 PSI piezo injectors, a complete fuel system-hardening to tolerate up to 20% biodiesel mixtures and urea injection (to reduce Nitrogen oxides) with a 5.3 gallon urea tank are updating the fuel and emissions systems. This engine has a fuel injector in the exhaust tract, to allow raw fuel injection during the particulate filter recycling routine. The RPO LML engine is rated at 397 horsepower (296 kW) at 3000 rpm and 765 lb·ft (1,037 N·m) of torque at 1600 rpm.
Roadmaster Engine has been rebuilding diesel engines since 1953. You can trust that the Chevy Duramax rebuilt engine will be the correct engine and one you can depend on.
Email us or call us at 800-447-9899 for any additional information you need.