https://autos.yahoo.com/gm-hit-102-6-million-152500503.html
3 replies (most recent on top)
If you watch "The Pentagon Wars" (free on YouTube), you will understand.
The AFM technology is not robust. If GM deactivated AFM, fuel economy would be reduced about 2 mpg highway. Some customers may sue over this since resale value of the vehicle would be impacted. Resale is impacted anyway, because most folks in the market for a used GM truck knows about the oil consumption issue.
This condition may be caused by two conditions. Oil pulled through the PCV system or oil spray that is discharged from the AFM pressure relief valve within the crankcase. Under most driving is discharged from the AFM pressure relief valve within the crankcase. Under most driving conditions and drive cycles, the discharged oil does not cause a problem. Under certain drive cycles (extended high engine speed operation), in combination with parts at the high end of their tolerance specification, the oil spray quantity may be more than usual, resulting in excessive deposit formation in the piston ring grooves, causing increased oil consumption and cracked or fouled spark plugs (#1 and/or #7).
Why would they keep selling it with the problem?
Why didn't they just fix it?