11.0 Oil Consumption: Notes

All engines normally consume a certain amount of engine oil. This is necessary in order to properly lubricate the cylinder walls, pistons, piston rings, valves and turbocharger(s), if equipped.

In addition, engines with less than 6, 000 miles will generally consume additional engine oil because the internal engine components are not fully seated (break-in). Therefore, engine oil consumption complaints received prior to 6, 000 miles cannot be considered.

Once a new or remanufactured engine has accumulated 6, 000 miles, oil consumption can be considered if there is a drastic change in the engine oil consumption rate (e.g., the engine oil consumption rate triples) under similar driving conditions.

Engines equipped with a turbocharger(s) will consume more engine oil than normally aspirated engines (non-turbocharged). The additional oil that is consumed in a turbocharged engine is mainly due to the turbocharger lubrication requirements. Some of the engine oil normally migrates past the turbocharger turbine bearing seals and will enter the intake tract of the engine. All turbocharged engines also require a complex crankcase ventilation system. The crankcase ventilation system needs to maintain a small vacuum on the crankcase and not allow the crankcase to be pressurized.

Pressurizing the engine crankcase can lead to external engine oil leaks and increased engine oil consumption via the piston rings and valve seals. When the load and the boost level of a turbocharged engine is varied, the path of the crankcase pressure is changed. During the crankcase ventilation path transition, a small amount of engine oil will pass through the crankcase ventilation system and is additionally consumed. The additional engine oil consumption of a turbocharged engine, as compared to a normally aspirated engine, is normal and not a defect.