A lot of 4.0s leak oil. It has no relation to the internal pressure. That sensor is a reflection of bearing health when working properly. Get the tester gauge.

 

++1 This is what I done for about $20. I mounted the gauge on a block of wood and set it on the dash. I ran the nylon tubing out the passenger side door (door gasket will allow this without pinching the line) and under the hood cowling. I used a 1/8 npt tee fitting so my in dash gauge was operative too. With this method you can see what your pressure is under all driving conditions. I would not be too concerned with low pressure at idle as long as it comes up when driving. I have had 4psi at idle for a long time. Dropping the pan to inspect your bearings (and pump) is a good idea but don't be surprised if they look ok.

 

what should the pressure be when driving? and idleing?

 

Above 1600 rpms psi should be 37+, at hot idle the psi should be 13+

 

okay thank you all

 

only true if clearances in engine are within spec. A tired engine will show lower pressure. Oil pressure is an indicator of wear and not a function....it does not always mean the end is near.

 

Hot idle minimum spec is 13 PSI.

You then need at least 10 PSI for every 1,000 RPM warmed up and running.

 

make sure ur engine is at running temp aka ur thermostat has kicked over. another thing that shows a bad oil pressure sending unit is if there is oil in the coneector.

 

I found, on my xy, the oil to came up to temp about 10-15 minutes after the coolant came up to temp.