223k miles, automatic, XLT, 2wd.

Truck did the random pressure normal to no pressure on gauge and a light would come on to the left. No noises. Engine speed or temperature didn't matter. But only did it for a few seconds every week.

Yesterday, I replaced the Oil Pressure Sending unit. 1-wire squeeze and pull off. Used 3/8-drive 13/16" deep socket, u-joint, 18" long extension going into drivers side wheel well, and ratchet.

Since a pump is inexpensive, not in the pan, and I have heard the oil pumps in these motors tend to go bad I figured I should go ahead and replace it. I see its an external pump between oil filter & block. I see the 6 bolts. Obviously there is a rod or something that goes thru the timing chain cover that drives the pump from the crank/cam? If so should I be careful that the rod does not fall out? Is there anything I should know before attempting this job?

 

No shaft to fall out.
Remove the pump.
Oil prime the new pump and align the Hex drive so the pump sets on the block and the O ring and draw up flat against the covers without forcing.
Do not rotate the engine with the pump off for any alignment. Turn the pump.
Oil pressure min. 45 psi at 2500 rpm hot.
Good luck.

 

Thanks for info.

Is the 2 different torque values in the attached diagram right for my application?
I believe the 18 lb-in should be 18 lb-ft.

 

The lower torque value is into a cover that won't take the same high torque without stripping the threads.
Good luck.

 

I ordered a Melling M246 oil pump from Autozone ($95). Attached are the instructions that came with it. They have different torque values then my previous post above that I just found on the internet: I believe the 18 lb-in should read 18 lb-ft. If you think about it if 10 Nm = 89 lb-in then how can 25 Nm = 18 lb-in? So the above is a misprint.
BTW, I was told the Ford 3.8, 3.9 & 4.2L v6 were basically the same block- which means external pumps on all.

 

The shaft can fall out-be sure its fully seated in the cam synchronizer. Speaking of which, its not the oil pumps that fail on these, its the gear on the cam synchronizer which wears and slips and no longer turns the oil pump drive shaft.