hey guys I bought a 2003 ranger edge with a 3.0 its got 235000 miles on it few weeks after I bought it oil guage started bouncing. I don't like fords dummy guage so I installed a manual guage and it shows 45 pounds cold after its hot at idle shows around 10 pounds hit gas back to 45 im just curious if this is normal and maybe the reason for ford installing a pressure switch instead of a sender or maybe time for a new pump

 

Just so everybody knows, if your Ford has an oil gauge, it's actually an idiot light. In other words if you have 5 psi or 75 psi, your gauge probably shows it in the "normal" area, perhaps halfway up the scale. If you had a genuine gauge, it would show high when the oil is cold and show lower as the oil warmed up.
Since your oil gauge was bouncing, I'm wondering if you just had a faulty oil pressure sensor. Have you replaced it yet to verify?
What oil weight are you using? If still using 5W20, you might try 5W30, as oil pressure actually drops as the bearing clearances increase in a engine with higher mileage. A thicker oil might help.
Years ago, I had an oil sensor catalog that showed the specs for various models. I remember one oil sensor that was set at about 2 psi. So if had this sensor on your engine, your oil pressure would show good at 3 psi, but would have your oil gauge drop to zero at 1 psi.
I'm not going to say that you do or don't have an engine problem, but 10 psi is probably enough oil pressure to keep your engine together, although ideally I'd want a little more pressure than that.

 

That is about normal pressure for an engine in reasonable condition. From somewhere, the ratio of '10psi for each 1k or rpms' is considered in the ball park. Additional pressure doesn't do anything to lubricate the bearings, though it might slow the oil flow, thus cutting down the flow of heat from the bearing in question. Besides providing lubrication, taking up the slack between parts, oil also carries away heat generated by friction. Rotating plain bearings have no metal-to-metal contact when rotating, riding instead on the oil itself. A pressure wave is created which holds the surfaces apart when in motion, but goes away whenever the bearings stop rotating.
If you are using 5W-20, it would not hurt to go to a higher viscosity lube. If you are in a warm climate, and don't have real cold temperaturs, going to a 10W-XX would not be unreasonable. The 5W oils provide quicker flow at startup, by some number of milliseconds(?), but with your vintage & mileage, I'd have no problem going to 10W, unless you lived in MN, up near the Canadian border. They know cold, as do the other states, where oil flows like thick syrup when cold.
tom

 

Yap first thing I did was replace the pressure switch that didn't work so I replaced the gauge still bounced right know I'm running a 89 sending unit and a manual gauge together dash shows middle of the gauge all the time with no bouncing but the manual gauge shows different as it should. Not sure about the oil have it serviced at dealership so I'm sure they put what it calls for in it

 

I'm in Alabama doesn't get to cold I'm gonna try 10w40 next oil change see if that helps I know I'm not gonna get a lot pressure hot because of Milage but I'd like a little more than 10 lbs

 

Check the wires coming from the sending unit for splitting or chaffing causing an intermittent ground issue.

Can the gauge be converted into a pressure gauge by switching out the sending unit?

 

Is there any kind of squeaking sound coming from the back of the motor?

The 3.0L vulcan is somewhat prone to camshaft synchronizer shaft failures. When a shaft fails (or is in the process of failing), oil pressure can fall off to zero.

What happens is, the gear at the bottom of the synchro shaft gets stripped because the shaft is binding on account of a lack of proper lubrication. (That's why there's often a squeaking sound associated with a synchro failure). Once that gear gets stripped, it can no longer spin the oil pump drive shaft, which means the pump stops pumping, the engine gets starved for oil, and then it's bye bye.

So you want to be absolutely sure it's a gauge issue, and not a synchro shaft that is beginning to fail.