The general concensus is that the oil is pumped in thru the fitting on the side near the top and out the bottom. However if you try to think of the route the oil takes, it seems backwards! At least to me but maybe I'm backwards. There are lots of holes in the filter and the oil has to enter it via those holes. It is cleaned (supposedly) and find its way out thru a hole in the tube down to the bottom of the canister and out. Would it not make more sense to reverse the lines and have it pumped up the tube and out into the filter, then thru the various holes and into the top/side outlet.
The reason I am asking all this is because mine was plumbed that way years ago when I got the truck and it worked fine. I had a constant oil pressure at any engine speed. after seeing many other installations and seeing a diagram, I rerouted my lines accordingly. The lines are new but now when I come to idle my pressure drops right off.
