[Obadiah]

The lower viscosity oils are not the issue. The issue with these GM engines is their Active Fuel Management (AFM) system which deactivates cylinders in the attempt to increase fuel economy. Their AFM system is completely defective and almost every GM engine with it has failed or will soon fail.

[Big Red Badger]

Thanks-—

[Celtic Conservative]

There are literally hundreds of youtube videos telling you how to deactivate that feature. My current car just barely escaped getting it as it was flex fuel compatible. The smaller displacement motor without the flex fuel feature has cylinder deactivation.

CC