First off want to say this is my first post. and Hi to all

I have a 97 F350 with 325k miles 5sp. It runs great and has no major issues but then the other day i noticed when I got on the truck hard to keep from getting ran over that the oil pressure above 2750 on factory gauge dropped and fluttered....so today I changed the oil and and added a mech gauge. I pulled the mech gauge off the port above oil filter. When I first started it pressure ran about 20psi then dropped to about 12-13 psi and stays there.. never changes more that 2psi no matter the rpm. Always above 10psi and below 15....the only other thing that comes to mind is every now and again when hot and i kill it it will restart then sputter and die but starts right back..but it doesn't happen that often

The truck runs smooth and has good power. It gets about 200 or more miles put on it a day...I really don't get in much hurry and usually don't wind it up much (60-65 with 4.10 rears). It has been well cared for with oil changed at 3000 since new. The truck does weigh up in the 14,000lb range (i know i know no comment needed) so it is always loaded.

I am debating on where to start first....I was going to put a LPOP on it and a front cover....figure its prob worn with all the miles. Then I read about the relief valves in oil filter/oil cooler housing getting junk in them and wondered..... My biggest prob is this truck cant be down more than a day or the weekend. I am planning on putting a rebuilt motor in it in the near future but i just got the donor motor the other day....so haven't even started rebuilding it.

Any advice would be awesome!

 

"Verify oil pressure using a known good mechanical gauge and measuring at the oil reservoir and at the main oil galley. Oil pressure at both points should be 10 PSI minimum @ low idle and 40 PSI minimum @ wide open throttle with the engine at operating temperature."

Is what the shop manual says.

 

I have a mech gauge on it now. just cant figure out why there is only 12ish psi even at 3000 rpm

 

Have you tried a heavy weight oil just to see if the pressure comes up some? Sounds like the LPOP is weak, Just guessing.

 

Figured out it was the Filter housing where the pressure regulator was falling out. Replaced and had 60 lbs of oil with 350k miles...so maybe it will make it to 400K...

 

Sounds good!