low oil pressure

[farmer]

i just picked up my first ranger for a song, its a 94 and its got the little 3.0, i was told these were notorious for low oil pressure but this thing stays right at the "N" in normal, is that bad? it also has a slight tick/tap that sounds like its coming from the driver side rocker area. i dont know much about this truck, it only has a 5 place odometer so I'm going to assume the 18xxx mi is 118xxx mi

 

[exbass94]

Go on Google and type in "Ford dummy gauge." The oil pressure gauge is as useless as a poop-flavored lollipop. Don't pay any attention to what it says, unless it drops to 0.

 

[Big Jim M]

When the pressure hits about 8lbs the sendor sends a signal to the gauge that tells the gauge to move to somewhere in the NORMAL range. The needle stays there until the pressure drops below 8lbs and then goes to zero.
AND that's all we need to know! We need to know if there is ENOUGH pressure to run the engine.. We THINK we must know more..but what would we do with that knowledge?
Enough pressure is enough!
Big JIm

 

[farmer]

ok thats good enough for me
now the ticking, it sounds like the drivers side. I'm going to pull the valve cover and take a look. if the rocker arms the problem, that should be obvious without disassembling it, correct? the next is take the rockers off and inspect the pushrods? if those are fine assume its the lifter?

 

[oldfordman]

BigJim has part of the answer, but not enough. the 8 psi needed to trip the oil sending unit (so the gauge jumps to normal) is enough to run the engine at idle, or a bit above. However, this is nowhere near enough oil pressure at higher rpms. The Ford spec for this engine is 40-60 psi at 2500 rpm. When I was building big block Chevys, the general rule was 10 psi per 1,000 rpm, which meant that to keep the engine happy, you needed 60 psi at 6,000 rpm. If the oil pressure gauge is steady at idle when the engine is hot, you are probably OK, but the real answer is to put in a real guage. Otherwise, if you want a little insurance, run a bit heavier weight oil. My 3.0 has 100K miles on it, and I'm running 10W40. Running fine. The 5W20 recommended by Ford was done to squeeze a bit more mileage for the CAFE standard, and for easier flow for those people in too big of a hurry to allow the engine to warm up a bit before they run them hard. In my opinion, 5W20 is too thin for high mileage engines. On all my engines, I have switched to a slightly thicker oil around 75K, and I routinely get 200K+ miles out of them. My S-10 just passed a quarter million, and only uses 1/2 quart in 3,000 miles.