New to Forum: How to tell type of Engine

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The 2001-2004.5 model year Duramax 6600 is an LB7, and the vehicle will have a number 1 (one) as the eighth digit of the VIN. Injectors and injector fuel return lines are beneath the valve covers.

The 2004.5- 2006.5 model year Duramax 6600 is an LLY, and the vehicle will have a number 2 (number two) as the eighth digit of the VIN. Injectors and injector fuel return lines are outside the valve covers.

The 2006.5-2007 model year Duramax 6600 is an LBZ, and the vehicle will have a letter D as the eighth digit of the VIN. The 2006 model year LLY engines are said to be the same as the LBZ, except for power/torque rating, ECM & programming and emissions certification.

The 2007.5 - 2010 model year Duramax 6600 is an LMM, and the vehicle will have a number 6 (six) as the eighth digit of the VIN. This engine runs with a Diesel Oxidation Catalyst and Diesel Particulate Filter, and requires ULSD (Ultra Low Sulfur Diesel) fuel.

The 2011-2016 model year Duramax 6600 is an LML, and the vehicle will have a number 8 (eight) as the eighth digit of the VIN. LGH (late in this year range as the eighth digit of the VIN), and the vehicle will have a letter L as the eighth digit of the VIN. This engine runs with a Diesel Oxidation Catalyst and Diesel Particulate Filter, and requires both ULSD fuel and Urea.

The 2017 model year Duramax 6600 is an L5P, and the vehicle will have a letter Y (eight) as the eighth digit of the VIN. This engine runs with a Diesel Oxidation Catalyst and Diesel Particulate Filter, and requires both ULSD fuel and Urea.


More info and additional details on all of these engines can be found in one of The Diesel Page's content areas (i.e. see the Duramax 6600 Diesel Page to learn more).

Jim