Originally Posted By: wjli
what happens when the filter gets clogged from being left in too long.
does the oil system bypass it or does it starve the engine for oil ?
Preventing oil starvation is the sole function of the filter's bypass valve, regardless if it's located in the filter or located in the engine block.
When a filter gets clogged, the pressure differential across the media increases. If that pressure difference exceeds the setting of the bypass valve, then the valve opens and lets oil bypass the filter media.