Excessive oil consumption in your 2018 GMC Sierra's V8 engine requires attention when you're adding oil between changes more frequently than expected. The Gen V 5.3L and 6.2L engines have experienced documented oil consumption issues related to several factors.
GM's Oil Consumption Standards
GM has stated that oil consumption up to one quart per 2,000 miles may be considered within acceptable parameters, though many owners expect less. Consumption significantly exceeding this rate indicates problems needing diagnosis.
Contributing Factors
The AFM system's cylinder deactivation can contribute to oil consumption. Piston ring design in some production runs created consumption issues. PCV system problems affect crankcase pressure and oil burning. Direct injection-related carbon buildup affects ring sealing.
AFM and Oil Consumption
During AFM operation, deactivated cylinders don't receive fuel but pistons still move. Oil can accumulate in cylinders and burn when they reactivate. Some owners report reduced consumption after disabling AFM.
Piston Ring Concerns
GM issued technical service bulletins regarding piston ring issues in certain Gen V engines. Some vehicles qualify for warranty repair. Ring design creates low tension that reduces friction but may allow oil past under certain conditions.