Quote:
Originally Posted by MAStuart
If they have a bypass how does much oil get filtered at all? |
All of it if the bypass pressure isn't exceeded.
The bypass opens when the filter inlet pressure exceeds the outlet pressure by the specified amount of the bypass pressure valve. That usually happens when the
oil is cold or when the filter media is plugged. Both situations cause restricted flow through the filter media so you want the bypass valve to open and allow the
oil to continue flowing. The alternative would either be no oil to the engine or burst media. Also a distinct possibility is the oil pump relief valve would open if oil couldn't flow through the filter.