oil filter anti drainback valve

[Mike Mulholland <meyeke@netinc.ca>]

i have noticed two things with the fram filters that i use in my 86 5kcdtq
which has 310,000 km and runs on mobil 1 15 /50.
1   the oil is still clean when i change it at ~5000 km.

2   when i unscrew the oil filter oil gushes out from around the gasket...i
assumed that this _trapped_ oil came from the head and other higher
passageways for oil.

also i'll mention that even driving hard through mountainous regions or just
fast on the flat i never have to add oil between changes. the dipstick level
drops an insignificant 1/16th- 1/8th inch.

ymmv

mike 

865kcdtq
84 5ks
845ksw