I feel I got a pretty good deal yesterday. Went to auction and ended up buying a 93 F-150 XLT 4x4 long bed ext. cab with the 5.8 160k miles. And it is CLEAN! Paint is still shiny, interior is original and perfect, AC blows cold, newer tires, aftermarket rims. It's a really nice truck overall. Wish I had snapped some pictures to share, will do here soon.

Anyhow, I was able to get it for $800. I figured at absolute worst case scenario, I could make that back parting it out.

It runs and drives perfectly, for about 10-15 minutes. Then the oil pressure gauge drops to nothing and the motor starts knocking. I'll shut her off real quick, let it sit for about 5 minutes and can start it back up and the knock fades away and it is good to go again for a little bit.

I flushed the motor and put some fresh oil in it, definitely didn't expect that to fix it but I was starting with the cheap and easy first. It did seem to help it a little but didn't fix it. Pretty certain I'll need to change an oil pump I just wanted to see what you guys thought.

 

Still sounds like a good deal. Maybe theres something blocking up the pickup on the pump, thats why it takes time to totally clog up the pickup, then it falls off when you shut down the truck. But if i were having to drop the pan to.find out, i would replace the pump anyway.

 

Thanks for the input. I definitely don't feel too disappointed about how much I paid, although I was really hoping I would luck out and get an issue free truck for $800 lol.

I had considered that maybe something sizable was floating around in the oil pan. If there is, it is kind of worrying to think what that could be and how it got there.

Trying to get a hold of a trailer to tow it from my dads house to mine so I can start messing with it. I would drive it home, but it would take a LONG time pulling over every 10 minutes.

 

Sounds like either excess gasket material, varnish/sludge, or other foreign matter is clogging the oil pump screen. I too think an oil pan removal and oil pump swap is in order. Perhaps a high volume unit while you are in there. If you find crud in the pan, It might be in your best interest to pull the valvecovers to see if there is more filth in the top end waiting to get flushed down to the pan and do it again in another 5,000 to 10,000 miles. If so, you might as well pull the intake too, and go nuts with a putty knife in the lifter valley and the valve rocker areas, and get that excrement out of there while the getting is good.

 

I would advice against the high volume pump though. Its really not needed and adds extra strain on the oil pump shaft.

 

I am going to agree with him about the high volume oil pump despite the fact that I personally would use one. The reason for that is because I have always had an (admittedly irrational) fear of insufficient oil supply. It might have something to do with my father's less than stellar maintenance on his cars when I was young. He always went over on oil changes, and so the bearings would rattle in his car ( even with fresh oil) and the oil light would flicker when idling with a hot engine because of it. I just remember the God awful warning buzzer on that 73 Montego, and how scary it was when the light on the dash lit and the buzzer went off sitting at a red light. In my 8 year old mind, I thought the car was going to blow up. Thankfully, I have reformed him, and he does much better now than when I was 8, but I can't get that insufficient flow thing out of my head. I know it is just a band-aid for worn bearings, but they don't call it "irrational fear" for nothing.