05 250 5-speed total oil pressure loss

At 110k mechanic diagnosed failing phasers from noise,rough idle, loss of power under 1k rpm. (Crew cab long box xl bought new for $25k)(first 100k were from carpenters (hard miles) so this truck is barebones and usefulness is much higher than cash value).

Truck has 146k

All symptoms typically disappear over 1k rpm so I have limited idle time and manipulated engine speed to try and maintain 1000-1200 and all has been well for past 36k miles. Today noise (valve clatter?) persisted at all rpm and during a scramble to get off the highway all oil pressure was lost (I'm aware that pressure gauge on dash is not 100% reliable). After total pressure loss I cut engine and called tow truck. Out of curiosity, I actuated ignition and motor cranked maybe two rotations, and then appeared seized. After about 45 min waiting for tow I went back to disengage 4wd and take my rifles and skis out of truck. At this time I actuated ignition again and engine fired and ran as it had for past 36k miles. I drove about one mile constantly watching oil pressure gauge, then noise returned followed by instant drop from normal to 0 pressure (dash gauge) I immediately shut of engine.

I am a mechanical engineer, but not a mechanic. I am familiar with the cam phaser system and I understand that their operation is directly related to oil pressure. Today's temp was under 0'F. I have a very skilled mechanic who works for around 30-40% of cost of licensed shop and I know his skills to be on par. I am looking for feedback, ideas,experiences, or any other valuable insight.

 

Sounds like you need to put in a new hart. Its been my experience with construction vehicles is they dont change the oil. They dont drive them nice. They operate in dusty conditions and they never replace the air filter. If you do replace the motor it would be a good idea to have the transmission looked at at the same time. I found this out the hard way. I did the motor in my 68 Mustang when i had it restored. I had the transmission on the floor and it was good so I thought. When the new motor was put back in the car i just stuck the transmission back in thinking it was good. It was fine with the old motor because it was tired and didn't have the power of the rebuilt motor. I had to pull the transmission back out and have it rebuilt. Sucks doing it twice.

 

another forum member recently had no oil pressure on 2 F-250s at the same time. it turned out he was using a version of 30W multigrade and due to weather should have been using either 5W20 or 0W20.

So pump failure and the like aside, its not impossible that your oil is too think to flow due to the cold and the problem could be as simple as oil and filter change to lower viscosity oil. I hope so anyway.

 

Thanks for your input. However I am using 5w20, and drop in pressure occurred at full operating temp, and after sitting for an hour, was momentarily fixed at cold temp, then dropped dramatically after 60 seconds of driving. I have seen several other threads saying the cam phaser issue could be remedied partly by switching to a heavier oil.

 

yes theres a SB or TB floating around that indicates you can quiet them down by using 10W40.

there are also mods to add washers with different size exist holes which help retain oil pressure....but I have trouble imagining that a total drop to zero PSI would be just phasor related. The phasors are pretty up stream from the oil pressure sending unit.

but nothing is impossible.

good luck on the search for an answer.