Was watching TFL Ike Gauntlet with the Ram 2500 and noticed something Interesting in the Rams engine bay shot.
Thicker hot viscosity in the Cold?
Thicker hot viscosity in the Cold?
Ram Cummins inline 6 oil cap oddity
- Thread starter thescreensavers
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Let me guess, you aren't familiar with CK-4 grades commonly available in the US market?
The sun and the snowflake also don't mean summer and winter. If you open the manual there's a temperature threshold. Lots of southern states qualify for sun oil grade in the winter, even if there's snow on the ground.
These are the ones that have major valvetrain problems on 15w 40?
The "problem" that is oil sensitive is attributed to deposits. Not grade, deposits.
The other "problem" is a machining issue that leads to lifter rotation and wipes cams. Also not related to grade. (Unless one suspects fuel dilution in which case the move from 15w-40 is headed in the wrong direction.)
Ah - so it's more likely that a 15w40 is going to be lower quality than a 10w-30 or 5w-40 diesel oil. leading to deposits which cause engine issues.
That is IMO the best of the conspiracy theories available amongst the internet experts. The "cold flow" experts will be along shortly to debate their stance(s). To which I will ask, well what is "cold." (The difference in 5w and 15w is roughly 10 deg C.)
The rub is that 10w-30 is not necessarily a grpIII product, so who knows what you're getting with T4 or Delvac 1300 10w-30.
EDIT: Also, the >2025 ram has moved away from the CGI block, which in theory would eliminate the second of the two issues I highlighted. In theory the cams/roller should no longer eat each other. The "deposits" issue would still remain unless they did something to make the lifters more resilient to that. (Shorter OCIs, which they didn't do. Indirect injector will help. Changes in NOx strategy could help if they did them.)
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Correct. I don't know much about diesel oils.
Thats been their recommendation since 2019MY trucks
“Changes in NOx strategy could help if they did them.)”
That one thing would help tremendously by not using as much EGR %, thus not as much soot in the oil and the increased diesel burning efficiency and increased temperature in the DPF to help keep it cleaned out. Let the SCR and DEF do the job it was designed for.
That one thing would help tremendously by not using as much EGR %, thus not as much soot in the oil and the increased diesel burning efficiency and increased temperature in the DPF to help keep it cleaned out. Let the SCR and DEF do the job it was designed for.
That's really what I was alluding to.
I think we'd all be surprised how much modern tunings prioritize in-cylinder NOx reduction (via EGR, but also delayed injection timing) and noise reduction at the expense of efficiency and soot output, and then count on the DPF to clean up the soot, using SCR to deal with any remaining NOx.
I'm just an armchair quarterback, but I'd rather see the EGR used as little as possible aside from warm-up duties, then run fuel delivery in a way that burns clean and efficient. This reduces soot load on the DPF. Then use DEF to clean it all up. Using more DEF at $3.50 a gallon isn't going to hurt me.
Perhaps this is the direction things are headed with smaller DPFs placed downstream of SCR rather than the reverse of 5-10 years ago.
15w-40, 5w-40, and 10w-30 are the popular API rated grades in the US diesel market, in that order. Browse next time you're in walmart. Since the time of straight grades, 15w-40 has been the most common, 5w-40 for extreme cold, including paw paw's tractor. Now even Class 8 trucks are moving to 5w-40 and 10-30. (Things like marine, railroad, stationary generators, and detroit 2-stroke are exceptions to my generalizations.)
I hear Canadians talk about 0w-40, but I have not a clue if that's typically found in an API or ACEA rating.
Chevron Delo XSP is available in a 5W-30 that holds all the important heavy duty diesel approvals, including CES 20086. It's the only one I am aware of. I suspect that we'll see more of this grade going forward and that it will replace the 5W-40 recommendation when(if) they become common in the marketplace.
Edit: now I'm aware of the Rotella and Delvac.
Delo 400 XSP 5W-30
Ed
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I don't disagree. Which is why post #5, which echos the consensus on the street because of some silly TSB that blamed 15w-40, doesn't capture the multiple issues going on in the 2019+ valvetrain failures.
We know that contact stresses between a roller lifter and a cam are, all other things equal, higher than those between a flat tappet and a cam. It's as simple as round to round contact vs round to flat, and the changing contact angle as the roller enters/exits a lobe.
Looks to me like spalling from a hertz stress fatigue propagation.
That points to an inclusion in the cam steel. Especially when the roller itself is still good.
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