The Duramax LMM is a 6.6-liter diesel engine used in 2007 through 2011 Chevrolet and GMC trucks and SUVs. When performing an oil change, or any project that requires the draining of the oil, it is imperative to add the amount of oil needed to meet the Duramax LMM's oil capacity. Failure to do so may lead to engine failure.
The Duramax LMM engine has a maximum engine oil capacity of 9.2 quarts without the filter being replaced. With a new filter, the capacity increases to 10 quarts.
General Motors recommends the use of API-certified 15W40 engine oil. In temperatures below 0 degrees Fahrenheit, 5W20 should be substituted to improve oil flow on start-up.
After filling the engine to capacity, always start the engine and allow it to idle for about 5 minutes. Then shut the truck down and verify the oil is at the proper level according to the engine oil dipstick.
