How do you choose your oil?

[Toxophilite]

Honest question - In what climate/condition would you want to run 10w-30 over 5w-40?

5w-40 is thinner at cold start and thicker at operating temps.

Obviously Ford recommends 10w-30 for "normal" conditions, I just don't see the benefit over 5w-40.

Seems like 5w-40 is a better option, regardless of conditions.

 

[JTredway]

Honest question - In what climate/condition would you want to run 10w-30 over 5w-40?

5w-40 is thinner at cold start and thicker at operating temps.

Obviously Ford recommends 10w-30 for "normal" conditions, I just don't see the benefit over 5w-40.

Seems like 5w-40 is a better option, regardless of conditions.

I forget what ford considers it severe duty but if it's good enough for that it's good enough for me. But if memory serves me it's not hard to touch or dance over the line and qualify for severe duty case. I run 5w40 bc it's safe for the severe duty and the wide operating range it covers. I am also in atlanta, so I can also be driving at 80mph one sec and then parked the next for 2 hours stuck in crap-ass traffic.

 

[Toxophilite]

Agreed on easily surpassing the line to "severe" conditions. Everything except the high idol times is "normal" for me. I have to believe that almost everyone that owns a Super Duty could say that one or more of the severe examples applies to them.

Hence my question, why would you run 10w-30? I don't think there is any downside in running 5w-40.

 

[JTredway]

Agreed on easily surpassing the line to "severe" conditions. Everything except the high idol times is "normal" for me. I have to believe that almost everyone that owns a Super Duty could say that one or more of the severe examples applies to them.

Hence my question, why would you run 10w-30? I don't think there is any downside in running 5w-40.

I'm with you probably no point honesty and just to give people an option and potentially a cheaper option.

Just checked Triax offers a 10w30 for 32.49/gal and their 5w30 is 33.49/gal but their 5w40 is also 32.59/gallon.

Might come down to just available options in various market regions. in theory 10w30 would also be better on fuel mileage (small percentage) being it's thinner at op temp.

 

[McE]

Agreed on easily surpassing the line to "severe" conditions. Everything except the high idol times is "normal" for me. I have to believe that almost everyone that owns a Super Duty could say that one or more of the severe examples applies to them.

Hence my question, why would you run 10w-30? I don't think there is any downside in running 5w-40.

My understanding is that 10w-30 is more shear-stable than a 5w-40 because it is less reliant on viscosity index improvers. The extra VIIs in 5w-40 can make it more susceptible to shear-down. This is generally true but can vary by oil depending on how it’s formulated, specifically the type of VIIs used. I’d still run 5w-40 over 10w-30 with reasonable OCIs.

I’ve run T6 in motorcycle transmissions and it does surprisingly well considering that’s a high-shear environment.

 

[Rich]

2nd time getting the oil changed on my "new to me" 2022 F350 6.7. After paying ~$240...I would like to start doing this on my own to help save a little (maybe) and give myself peace of mind from the hooligan show I saw today.

How do you choose your 13qts? Cheapest that meets the reqts? Brand that you've learned, know, and trust? Taste and smell? Some other fascinating criteria?

My '20 has over 100k on it using 10-30 Motorctaft Diesel Oil, and Motorcraft filters....yep, stock oil, stock filters, no issues at all. Starts at -35° without being plugged in, has no oil usage between changes, no high oil temps while towing. Just sayin'