Ok guys I need some advice. I just overhauled the engine in my 89 F-350. Fired it up to discover little to no oil pressure at idle and 15-18 if I rev it a little. So I put my mechanical guage on it. Confirmed my electronic guage readings. So I'm thinking the regulator valve is stuck. Pulled the cooler and checked it all out and it seems to be operating properly. So while i had the cooler off I cranked the engine over, watching the oil port where the cooler mounts in the front and I'm hardly getting a trickle. Added an extra gallon of oil and got the same result. Everything is new in this engine...Oil pump and pick-up tube too. Is there a port I could have missed putting a plug into between the pump and that oil cooler port that could be bleeding pressure off? I'm prepared to pull the engine to examine the pump and pickup tube if necessary. At this point I cant think of anything other than a faulty oil pump or cracked pickup tube. I thought id run it past you guys first in case I'm missing something. Thanks in advance!