Hello,

Recently acquired a 74 F-100 It was sitting for the best part of 8 years. With 180,000 miles on it, the engine runs great with plenty of power and no noise. Smooth like a sewing machine, but noticed the dash gauge read good oil pressure until warm and the needle would peg to the N of normal.

So I installed a mechanical gauge and it reads as so, 40-50 psi idle and drive when started and falls to 30-40 cruising hot and 0 psi at hot idle in gear. Bumps up to about 20 when parked.

No noise, no smoke, no problems.

Could there be something other than wear causing this? Bad oil pump, galley plugs, etc....?

 

That's normal with an old engine with lots of wear. The Clevelands were famous for it, but mostly due to the sensor being at the rear of the block. When it warms up, the oils viscosity thins out, that combined with the loose clearances in the motor does it everytime.

 

Ok, should it have some more life in it or is it going to start knocking any day ?

 

If it does start knocking, that'll be the #4 & 8 rod bearings going south. Those are the last in the oiling system, furthest from the pump. I wouldn't worry too much, long as you have at least 40 psi up off of idle.

 

If you want to save what's left you could drop the oil pan and change the oil pump. Swap it out for a high volume, high pressure pump,. If you can't find one in both specs, get a high volume unit. Might also try first, changing oil to 20w50 and adding a bottle of STP oil treatment. Then see if the pressure improves before changing the pump

 

She is just wore. It could last for years. It could come apart tomorrow. A pump might help might not. A refresh would fix it. new pump, new bearings. Your call your money your truck.