I am pretty sure I have a bad oil pump, but I want to get your input. Oil pressure dropped to zero when the truck was hot. It was fine while it was running and still cold. I am sure it is the pump. Do you agree? And juts how bad a job is it to replace the pump? I see that the oil pan extends above the top of the cross frame but there may be enough room to remove it. Or not? My manual and tools are 180 miles away at the moment.
BTW we're talking about a 1999 F-150, 5.4ltr.

 

Update. I assumed the oiol pump was like in my '84. I went on line to find one and discovered it is nothing like the old truck. It appears to be mounted to the from of the block. Can someone verify this?

 

I'm pretty sure it's on the front of the crank,just behind the timing cover.
I know I have a 5.4 in my shed with the pump on the end of the crank but the cranks not in the block and it's been a while since I took it apart...lol

 

To change the oil pump in a modular,you need to remove the oil pan,timing cover,the cam covers,timing components(chains,etc), then remove the pump. It's driven by a pair of flats on the crankshaft's nose. First thing to do is check the oil pressure sending unit-they are notoriously flaky and will give false readings of no pressure. Best way to double check it if you're concerned-buy a cheap mechanical pressure gauge from the auto parts store of choice,and temporarily connect it just to monitor pressure to verify with a real gauge that the oil pressure is going away.
JL

 

Thanks for the reply. Unfortunately I know the sending unit is good because when the pressure dropped I got all sorts of clacking noises. I have retrieve my manual and most of my tools. I have also read the procedure and it is a scary job. The shop calls for 8.4 hours so I figure 12 minimum. My problem right now is finding the cam locks and the crank lock so nothing moves when I remove the timing chains. I also need that special tool to get the fan and water pump off. Chilton's says that tool is available from most auto parts stores. But, of course, when I checked at Autozone yesterday they didn't have one. I have to drive all over College Station to find the stuff. Once it is in hand I can start. Just hate to do all of this just to find out it was something else. But nothing else makes sense and has the same symptoms.

 

You don't need either of those cam or crank tools-just retime the engine before putting the chains back on-it's relatively simple,and you know it's right. I think you're probably gonna find the timing chain guides worn down,and a bunch of nylon on the pickup tube when you pull the pan. I've seen that many times when the oil pressure is actually low on these engines. There's no special tool necessary to remove the fan clutch-it's just a bit of a hassle. The water pump doesn't need to come off either-it can stay in place.
JL