Got a Ford F150 1997, installed a new long block motor 4.2ltr, new oil pump, new water pump, etc. No oil pressure. disconnected oil sending unit and inserted a oil pressure gauge into to oil pressure sending unit hole and no oil pressure. The engine was properly primed and the new oil pump was switched out to be sure that was not the problem. With the oil sending unit hole free of the oil sending unit and the gauge, when the motor is cranked (not started) oil will shoot up out of this hole, but yet when a gauge is hooked up there is no oil pressure. Can anyone tell me what's up?

 

Is the motor knocking? What other evidence than the sender or your oil guage that you have no oil pressure? Senders are a comonly failed item on these vehicles and an air pocket in a guage could cause a false reading.

 

The valve covers were loosened and the engine was cranked and there is no oil being pumped up into the valve, lifter area. (Sorry I'm a woman and am posting this for my husband). It seems like the engine is unable to hold oil pressure. Because it is pushing oil up out of the oil sending unit hole, we are assuming that the oil pump is working and that the pick up tube and screen are in correct working order. This is a new motor purchased from ProPerformance and our mechanic us ASE certified. We are pretty much dumbfounded by this. Any suggestions? Ford says it sounds like we were sold a bad motor with too much space between the bearings.

 

You may have better luck in the 4.2L forum further down the main forum page. I am not sure how the oil makes it to the lifters on these. Is the cam sensor installed (where the distributor used to go)? It may have to pass thru it to reach the top of the engine.

 

Found out the problem.....the pick up tube and screen are too close to the oil pan. They are hitting the bottom of the oil pan creating a vacuum and shutting off the oil from the tube. Had to take the motor back out of the truck since you can't get the oil pan off while it is in the truck (not enough clearance). Which was not fun, but at least we found the problem. thanks to all though.

 

Glad to hear you git it fixed