Hey guys, has anyone run a heavier weight oil in their 7.3 other than the recommended 5W-30? I’ve heard of fleet mechanics running up to 15w-40 oil in their 7.3s to keep oil pressure up. I have run Schaeffers 9000 5w30 since my first oil change.
I have a 22’, manufactured in early 2021. My truck only has 26k miles, most of them are towing 5 to 10k pounds. My 5/60 powertrain warranty will expire in Aug. 2026. I am terrified of a lifter failure outside of warranty… I would like to do anything I can to prevent it if possible. Hopefully it’s not inevitable.

 

AI says. ...... the 7.3 uses a variable duty cycle and a PCM-controlled IPR (Injection Pressure Regulator) to manage oil pressure. The IPR acts as an electronically controlled bypass, bleeding off excess high-pressure oil back to the oil pan to regulate the pressure as needed by the engine.

• How it works:
  The Powertrain Control Module (PCM) controls the IPR's duty cycle, which determines how much high-pressure oil is allowed to bleed off back into the system. This allows the engine to operate with different oil pressures based on the conditions, which is often lower at idle and higher under load"

So, wouldn't using an extra high viscosity oil actually reduce oil flow to lifters?

 

I've run Schaeffers 9000 5w30 since the first oil change and I'm at 58k miles. I'm not concerned about an oil related failure. The needle bearings in the lifter will fail if they're going to fail and no oil in the world will save them. The oil pump programming recall doesn't even cover anybodies trucks. Just ask someone who owns one to plug in their VIN.

 

First 100,000 miles or so MC semi synthetic 5w30 since then Mobile1 full synthetic 5w30. Now at 228,002 miles.... stopped thinking about lifter issues awhile ago. LOL

 

Refreshing to hear. What model year is your truck?

 

2021 F350 SRW Supercab XLT 4x4 7.3 3:73 E_locker

 

MC full synthetic since my first oil change. No issues. Far less miles then Scraprat but basically the same truck.

 

If you are terrified of something failing outside of the warranty... get an extended warranty. Outside of neglect, or doing something dumb (like running 15w40, which is not one of the recommended oil grades for a gas engine) either something will fail, or it won't... that no amount of 'maintenance' will prevent, outside of tearing the engine down to examine the components in question.

Quite honestly, I expect either lifter failure, or the transmission to take a dump prematurely... I would not be surprised to see it happen as soon as tomorrow, and I won't be surprised if it never happens, either. It's just a mechanical device, assembled by humans.

 

"AI says" makes my skin crawl. I don't doubt that some day it will be good, but what you've got above is a mix of false things, correct but in the wrong context things, and correct things thrown in a blender to see what comes out. In this case the conclusion is accidentally correct. Yet the 7.3 gas engine does not haven a IPR. An IPR does manage oil flow via pressure, but not engine lubrication oil pressure. It manages fuel injection oil pressure for HUEI systems, which is what the 7.3 powerstroke uses - a completely different platform. AI will often jumble things that require context like this, the 7.3 gas engine vs the 7.3 powerstroke engine. Both use a variable oil pressure control systems but for 2 completely different purposes and bringing up an IPR is wholly irrelevant.

Don't go to AI looking for answers, unless you just need to be reminded of something you knew but can't recall at the moment because it does crap like this all the time. If you don't know and want to learn something you need to go to source material for yourself. AI crosses wires like this all the time.

But as I said, the conclusion is accidentally correct. Yes oil flow is pressure regulated so using an oil weight that is more resistant to flow and regulating it to the same pressure means you're reducing the flow of oil through the system.

 

I have used 5w-40 API SN in my 7.3 gasoline engine since the 1,000 mile mark, UOA reports are in this folder. Yup, grade and API spec does not match Ford's recommendations, but it is my engine for the long haul, not theirs. I also run this oil in Honda's, Subaru's, other Fords, antique gasoline tractors, modern diesel tractors, and every small gasoline engine in my barn.

 

I've used Delvac-1 5W40 since 1,000 miles. It shows the same 21psi at hot idle as the factory fill 5W30 did because oil pressure is PCM controlled.

You can unplug the pressure control solenoid and it will default to whatever the "full" pressure the spring acting on the vane pump allows. But it will set the CEL because oil pressure commanded will not match actual.

 

I know the "variable" battery charging is adjustable via Forscan, because I've changed mine on my F-150. Is the variable oil pressure adjustable with Forscan as well ?

 

It is not.

 

194k miles now, changed oil every 9-10k miles with MC 5w-30 synthetic. No engine issues, transmission replaced at 190k.

2022 F350 chassis cab, truck weighs ~12,000lbs all day, every day

Don’t overthink the oil. If the lifters are gonna fail, they’re gonna fail.

 

Growing up in the 70’s, seems it was common to run heavier viscosity oil. Having gone to some oil analysis classes for industrial oil programs, my mind was changed on the notion that heavier oil is better. I run 5w30 full synthetic in every gas engine I have, vehicles, mowers, etc. But technically 5w30 is heavier than the recommended oil in ours Subaru, but it’s easier just to have one oil for everything.