Several factors contribute to this engine inherently running warmer than its LB7 predecessor (or the engines that followed it), one of which is the fact that LLY-powered GMs came equipped with the smallest radiator ever offered in front of a Duramax (yet had an additional component to cool it in the form of the EGR cooler). In reality, not all trucks overheat, but it’s a common enough problem that it gets a considerable amount of negative attention. The commanding issue most LLY owners worry about is this engine’s tendency to overheat, especially when towing. OHV, four valves per cylinder, single camīosch high-pressure common-rail, direct injectionĥ20 lb-ft 1600 rpm (early '06: 605 lb-ft 1600 rpm) LLY Hard Facts ProductionĬast-aluminum with six 14mm diameter head bolts per cylinder (with sharing)

Make sure to check back in for Part Three, as we’ll be exploring one of the most coveted Duramax engines ever built: the LBZ. For all the dirt on this briefly-produced and often-overlooked oil-burner, keep scrolling. But even though it tends to be viewed as the least desirable in the Duramax lineage, the LLY was a very solid engine. While previous injector issues were laid to rest with the LLY, the common-rail injection system still had a few minor quirks, along with the injection system still being void of a factory lift pump. Issues with overheating, brought about from various different components, proved to be its biggest drawback, often contributing to higher operating temps and sometimes even blown head gaskets. However, despite its improvements and added technology over the LB7 the LLY wasn’t without its own shortcomings. Later model LLY mills (‘06), which arguably had more in common with the LBZ that followed the LLY, packed 605 lb-ft of torque. On early versions of the LLY (’04.5-’05.5 model year GM trucks), horsepower climbed by 10 to 310hp while peak torque remained at 520 lb-ft-but became available 200 rpm sooner in the power band (1,600 rpm vs. Although much of the LLY’s internals match what you’ll find in the LB7, this version of the 6.6L V8 brought an improved injector design, variable geometry turbocharging and cleaner emissions to the table. Midway through the 2004 model year, GM released the second-generation Duramax, RPO code LLY.

Lb7 coolant capacity