Stellantis 6.7L Cummins TSB: Only use 10W30 on 2019MY+, 15W40 can cause damage

[The Critic]

https://static.nhtsa.gov/odi/tsbs/2020/MC-10178698-9999.pdf

Was advised by a few reputable dealer techs than 15W40 was causing the pushrod and rocker arm issues, and this is one of the reasons why Stellantis came out with this TSB.

Any thoughts on this? Surprised to see a 15W-xx oil cause issues compared to a 5W-xx or 10W-xx in >0F conditions.

 

[RamFan]

Interesting! Especially with the recent 10w-30 thread that popped up the other day.

 

[wwillson]

I would need to see a detailed explanation about how 15w-40 causes deposits to form.

 

[kschachn]

I would need to see a detailed explanation about how 15w-40 causes deposits to form.

Yeah I’d love to see that too. Grade in and of itself doesn’t have a thing to do with it.

 

[The Critic]

I would need to see a detailed explanation about how 15w-40 causes deposits to form.

It must be from breakdown of the VII.

 

[Hall]

Any thoughts on this?

If they are unequivocally saying NOT to use it, you can be certain that they have very good reasons to back that up. They are also taking an across-the-board restriction by not getting into the temperature/climate of where the engine is operated. Just easier that way....

 

[Rand]

It must be from breakdown of the VII.

That would be odd considering they are saying you can use 5w40 in the same truck.

 

[The Critic]

That would be odd considering they are saying you can use 5w40 in the same truck.

Since most 5W40's are synthetic and most 15W40's are not, I'm guessing that higher quality VII's are being used in the 5W40's.

 

[Hall]

That would be odd considering they are saying you can use 5w40 in the same truck.

What makes an oil 5W vs 15W ? Could there be commonly used components across the major 15W-40 producers that are the concern ?

 

[Rand]

Since most 5W40's are synthetic and most 15W40's are not, I'm guessing that higher quality VII's are being used in the 5W40's.

maybe, maybe not. Their statement is very blanket and terrible. IMO.
OTOH I'd probably be running 5w40 anyway.. I guess in CA many would run 15w40 year round.

Its ok as a TSB perhaps as far as TSBs go... but I'd definitely like more details.

 

[The Critic]

What makes an oil 5W vs 15W ? Could there be commonly used components across the major 15W-40 producers that are the concern ?

Cold flow properties...

 

[OVERKILL]

Amusing. So, conventional 15w-40 oil, no go, but synthetic (5w-40) you are G2G.

 

[The Critic]

Amusing. So, conventional 15w-40 oil, no go, but synthetic (5w-40) you are G2G.

I have a feeling there's more to this story that they are not disclosing...

 

[OVERKILL]

I have a feeling there's more to this story that they are not disclosing...

Yes, I'd love to know the juicy details!

 

[Jetronic]

Amusing. So, conventional 15w-40 oil, no go, but synthetic (5w-40) you are G2G.

I think that would be it, yes. Low oil flow in the valve lash adjuster, so the mineral stuff is likely to largely stay there after oil changes and degrade further into the next oci... once the thickening starts it will be even harder to get out.

 

[Hall]

Cold flow properties...

Sorry, I meant what "ingredient(s)" change the cold temperature viscosity between a 5W and 15W. One has to wonder if 15W-40 synthetic (if available) would have been okay.

 

[PimTac]

So the simple way forward would be to use 5W-40 no matter where you are? That seems to be the gist of the matter.

I wonder what is so different on the updated valve train?

 

[RamFan]

It must be from breakdown of the VII.

That's my assumption as well.

 

[OVERKILL]

Sorry, I meant what "ingredient(s)" change the cold temperature viscosity between a 5W and 15W. One has to wonder if 15W-40 synthetic (if available) would have been okay.

The base oils.

 

[CumminsMech]

Interesting, I haven't heard a peep about this at all. But, as far as I know, were aren't using any hydraulic valve lash adjusters on the commercial B6.7's either. So that's probably why. The Ram versions do have quite a few differences vs our commercial engines. Our commercial engine owner's manuals for 2019 and older still state "While the preferred viscosity grade is 15W-40, lower viscosity multigrade oils can be used in colder climates." Newer model years states "Use of 10W-30 is recommended for normal engine operation and provides the best wear protection. 15W-40 is compatible for improved engine durability at extremely high ambient temperatures."