The Duramax LLY was introduced to the market mid-way through 2004 and due to changes in the industry and the rising standards in emissions regulations, its lifespan was shortlived. However, even though it wasn’t around long, it made its mark by introducing new technologies.
The LLY in Duramax LLY is an RPO (Regular Production Option) code indicating that the engines with that designation came with EGR (Exhaust Gas Circulation) on them. EGR controls NOx emissions by lowering the oxygen concentration in the combustion chamber, as well as through heat absorption. +Read more
Compared to its predecessor, the LB7, the Duramax 6.6L LLY has an improved fuel injector design, a variable geometry turbocharger and was cleaner running due to the improved emission control features. Another improvement of the LLY was in the power department. The Duramax LLY has an increase of 10 horsepower. Measuring in at 310 compared to the LB7s 300 horsepower.
The 6.6 Duramax wasn’t perfect, it had some problem with the injector harness and a restrictive inlet horn but those problems were easily fixed. Additional mechanical problems include the LLY overheating. The higher operating temperature of the LLY contributed to blown head gaskets. The common rail injection system also had a few issues and the injection system didn’t come with a factory lift pump. Despite those issues and its reputation as the least desirable amongst the Duramax diesels, it is a very solid engine.
If these or any other problems have come up with your Duramax LLY, ProSource is here to help. Whether you need Duramax engine parts or Duramax LLY upgrades, we have the diesel parts you need. If you have questions send us an email or give us a call at 1-800-489-6820