How long have you ran it??...sometimes it takes a few to get primed up...seams odd that just changing your oil would cause a lack of oil preasure...

when in doubt..knock`um out...(or wish ya had later!!)...H.C.C.M.F LOCAL 6978

Flint Michigan..most dangerous city in the USA..come back and visit us..sorry we "missed" you the first time..LOL
"Flint 'Vehicle City' Now America's Murder City"

Officially #1..
http://finance.yahoo.com/family-home/article/112804/most-dangerous-cities-247