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Discussion Starter · #1 ·
I've noticed on 2 trucks now that on startup, there is occasionally a delay in building oil pressure for up to 10 seconds. i know there are a couple check valves in the oil cooler assembly, so I'm wondering if maybe one of the valves gets stuck open once in a while and it drains all the oil back into the pan? This happened twice today on one of my trucks, and I have to admit, it was a little nerve-wracking watching the guage sitting at 0 psi while the engine is running.

I do know it's not the guage because as soon as the pressure comes up on the EVIC the engine becomes slightly quieter. Anyone else run into this?
 

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2015 Outdoorsman EcoD CC w/6.4' 4X4
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The oil pressure reading on the dash is not a real pressure reading, it's a calculated value based off of engine rpm and oil temperature. You can't go by the oil light either as it illuminates for a few seconds upon start up or turning the ignition on when remote starting as a part of the dash cluster self test.

At least the oil temperature is real, unlike the Cummins trucks where the oil temperature and pressure are both calculated values.
 

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2015 RAM 1500 CC 4x4
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Its possible the anti drain back valves are sticking open thus requiring time to prime the system. Its not normal or correct for this to happen on these engines.
But, like Crash said the gauge is just a calculation, not a real pressure reading, so whatever he is observing on the gauge is not indicative of an issue.
 

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But, like Crash said the gauge is just a calculation, not a real pressure reading, so whatever he is observing on the gauge is not indicative of an issue.
Its a switch but it does indicate if pressure is below the minimum closing pressure aka about 8 psi. 10 seconds on startup means the oil filter and or oil cooler are draining back which they shouldn’t.
 

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Is the analog gauge reading zero hooked up to the pressure switch? I would think the red flashing low oil pressure light is activated by the low pressure switch and the analog gauge only displays the calculated number.

I do not have the analog gauges with my tradesman cluster, but the digital oil pressure readout typically reads a number above zero even before cranking.
 

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Discussion Starter · #7 ·
Its a switch but it does indicate if pressure is below the minimum closing pressure aka about 8 psi. 10 seconds on startup means the oil filter and or oil cooler are draining back which they shouldn’t.
This is kind of what I was thinking. Strange that it is somewhat intermittent, though. I'm going to do a cold start this morning and see what happens.
 

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Discussion Starter · #8 ·
Prior to starting this morning, I gave the oil cooler housing a few raps with a plastic hammer. Once I started it, there was about a 1 second delay and the oil pressure shot up to 53 psi.

I think maybe I need to start disassembling the oil coolers and cleaning all the check valves when I go through these engines in the future. Thanks for the input guys!

By the way, i pulled the original engine I rebuilt with the King bearings. It had that oil leak that I could not fix. It has about 7k miles on it, so I will take some pictures of how the bearings look when I pull the bedplate to re-seal it.
 

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2021 Ram 2500 Tradesman Crew Cab 6.7 L Turbo Cummins 3.73
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IF you really want to know what your REAL oil pressure is, do what I did, install a real pressure gauge. I would see north of 100 psi when I started in the cold mornings.

 

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Discussion Starter · #10 ·
IF you really want to know what your REAL oil pressure is, do what I did, install a real pressure gauge. I would see north of 100 psi when I started in the cold mornings.

Nice write up! If I was planning to keep the truck I would definately do this
 
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