In checking out Amsoil filters for my application(chevy 5.3L engine)I found out that the SDF64 filter does not have a anti-drain valve. However, the AC Delco PF59 which is the regular equipment filter does. I also checked on a Baldwin #B1432, Hastings LF487, & a Mobil 1, M1-206. All of these are replacement filters for this engine and they all have the anti-drain back valve. I wonder why the Amsoil filter doesn't. Does anybody have any ideas?
Thanks.
Thanks.