91 Montero with external oil cooler.......Help! Tried both electrical oil pressure sender and mechanical with same results....instant 80 psi oil pressure reading!!!! I know there is no oil flowing as I just froze an engine late last year with this same psi reading and could clearly hear extremely noisy valves/rocker arms......20 seconds later.....SQUEAL!!...FREEZ-UP!! I have checked all oil lines and cooler-no blockage. This is a brand new block and heads(I did prime both the oil pump and block) Is there some kind of pressure valve in the oil filter housing. Any ideas??