I don't remember how oil gets into that pump, whether the pickup tube bolts to the pump, or there's a passageway in the block from the pickup screen to the pump, but look for anywhere air could be drawn into the inlet side of the pump along with the oil. A leaky gasket where the pickup screen bolts to the pump is the most common cause, but a cracked pipe on the pickup could happen, etc. Just make sure the pump sucks up only oil, not air along with it!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!