Low Oil Pressure Warning

[Michael Edwards]

I think I’m looking for more of a confirmation than a diagnosis…I hope! Ha
Was driving down the interstate at speed, pulling approximately 3500lb trailer…pulled same load the other direction 6 days earlier without issues, but about 200 miles in, my low oil pressure warning comes on and immediately goes off. It did this numerous times the last 150 miles of the trip.
Now before you all go off on why I didn’t stop…there was zero change in the motor, zero loss of power, zero knocking noise, temperatures were fine (been running littler warm 115° to 125° depending on pulling hill or not, but was pulling a load). I did check oil level once home and was normal level.
My non-mechanic ***, feels like it is a failing oil pressure switch.
Am I correct, or should I be looking at a possible motor replacement, for being ignorant….‍

 

[TwizzleStix]

Are you checking the oil on a level surface, such that the truck is level and not nose-high with trailer attached?
Cause could be several things…

1- low oil level

2- connector/wiring issues at oil pressure sensor and/or oil pump. Note the 2stage oil pump runs at a lower pressure (~20psi) while cruising at light load vs (~60psi) at heavier load with more throttle

3- oil pump pressure-switching solenoid.

 

[Michael Edwards]

TwizzleStix thanks for your thoughts. First as stated I’m no mechanic, but yes I checked the oil levels without the trailer and level. It was right at the full line.
As for the rest of what you stated…that’s where the “non-mechanic” comes into play.

I have the new pressure switch, and will clean the electrical connections when installing.

As for the “oil pump pressure-switching solenoid”…not sure…actually no idea…where it’s at or how to check it…

can you point me in the right direction and I’ll for sure check it

 

[Jason Krakauer]

May be unrelated to your issue - but when I went through an intermittent "low-oil-pressure" warning - turns out my bearings were shot. Best suggestion is to see if you can find a shop that will put a reader on the truck while it's running that'll show oil PSI real-time. My oil levels were fine, I replaced the pressure sensor (because shop and I thought it was possible that this was the issue too), and still had the problem.

When we hooked it up and ran it - you could see real-time PSI was single digits at idle and not much higher under load. Confirmed bearing material in the oil through Blackstone analysis (after the fact). Had to replace the motor.

 

[2slo4u]

When I had the "low-oil-pressure" warning, they replaced the sensor but that did nothing to fix the problem. Turned out that oil from the cracked valve cover had eaten through the protective coating on the wiring. Took the dealership about a week to figure that out.

 

[FordTechOne]

Are you checking the oil on a level surface, such that the truck is level and not nose-high with trailer attached?
Cause could be several things…

1- low oil level

2- connector/wiring issues at oil pressure sensor and/or oil pump. Note the 2stage oil pump runs at a lower pressure (~20psi) while cruising at light load vs (~60psi) at heavier load with more throttle

3- oil pump pressure-switching solenoid.

To clarify...OPs truck is a Gen 1, so no 2 stage oil pump.

With the warning light coming on erratically, chances are high it’s the oil pressure switch sender or a damaged circuit.

 

[TwizzleStix]

To clarify...OPs truck is a Gen 1, so no 2 stage oil pump....

Well, duh. I blew right past that part!