[jetjock15]

I LOVE LAMP

 

[jetjock15]

Didn't the OP say that the truck was a 2005? Don't be giving him information based on the "new and improved" 6.7 or 6.4. Either way the book on the 2020 6.7 only specifies 0W30 for extremely cold climates. (Like the North Pole) This is from my 2020 owner's manual for the 6.7 diesel.
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I'm still standing by my opinion unless you can show me in the 2005 diesel supplement specifically for the 6.0 engine. I checked. Ford no longer lists 2005 model year on their website for owner manual download. If Ford engineers did not specifically recommend it Don't use it. I'm just trying to save the OP some grief.

Did the original post get deleted? First post I see is you asking a bunch of random questions. Is this thread a part 2 to something else? I’m lost

 

[jetjock15]

@bismic

Just curious, don't know if you would have the data, what happens to the viscosity between 0w40 and the 15w40 as the temperature go north of 212? I would imagine it's not uncommon for a lot of 6.0s out there to run significantly hotter on a regular basis due to subpar or clogging oil coolers. If you already posted info that says this my apologies. I'm guessing the 0w40 would do better as their synthetic, but don't really know

All else being equal the one with lower spread has less modifiers and would hold properties better. But the 0W40 is synthetic so it will have some superior properties. Oil doesn’t even start to break down till 280ish and go well north of that. Mobil had a claim once it could hold together till 500. When I worked in that race motor shop a lot of customers wanted do talk about this so we had a lot of knowledge based on real world testing

 

[jetjock15]

Interesting when I first started being involved with that shop and off road racing the shop owner sold VR1 20-50 with every motor. After 3-4 years of tracking rebuilds and recorded temps we switched to 10-40 and then 10-30. We had best results with 10-30. And the temps in a race would be 30–40 degrees lower with 10/30 versus 20/50. That would be internal friction I guess just real world data. The overall lower temps helped all the motor systems last longer. Now customers get 10/30 or 10/40 depending

 

[jetjock15]

I understand that is the theory, but it is not backed up by engineering data. It is only a matter of opinion. Without engineering data, I would not recommend it, especially if normal engine temperature at startup is above -15°F.

You are joking right? Just checking, even humor and sarcasm can be hard to gauge on here. If your serious… wow.