[Captainmal]

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

Service bulletin on oil selection for Cummins engines. The last part is of importance to both earlier ( pre-'19) and newer (post '18) engines.

 

[BrianF]

I sure would like to know how oil viscosity could cause deposits.

Oh well, I will keep running my 10w30.

 

[RossCountyRam]

Seems to me that in pressing these engines (generally speaking) to extremely tight tolerances making oil selection so critical, the manufacturers are creating potential problems rather than solving them.


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[howie12]

It is hard for me to comprehend the concept of 0w40 being OK all year around for both engines if you live in cold country but if not you must use 10w30 for the 2019 and newer engines coupled with the fact that this oil must meet a Cummins spec and API CK-4 and the 0W40 can be CJ-4 and doesn't have to meet the CUMMINS spec.

I don't have a Cummins so won't take the time to go to BITOG but lots of experts there and perhaps they have an explanation. If anyone does either have one or find one please post it up here. I'd be interested in reading it to see what I can learn.

btw, Cap you might want to reread your note and correct it.

All the best,

 

[Brokedownbutgood]

It is hard for me to comprehend the concept of 0w40 being OK all year around for both engines if you live in cold country but if not you must use 10w30 for the 2019 and newer engines coupled with the fact that this oil must meet a Cummins spec and API CK-4 and the 0W40 can be CJ-4 and doesn't have to meet the CUMMINS spec.

I don't have a Cummins so won't take the time to go to BITOG but lots of experts there and perhaps they have an explanation. If anyone does either have one or find one please post it up here. I'd be interested in reading it to see what I can learn.

btw, Cap you might want to reread your note and correct it.

All the best,

Not sure where the 0W-40 reference is coming from but the new 6.7 uses either 10W-30 or 5W-40. One big difference is the new 6.7 has hydraulic lifters which needs the oil to keep them pumped up correctly. Cummins has approved 5W-40 for years and lots of oems are going to 10W-30 now for fuel economy.

 

[bobcat67]

Ford has spec’d 10w-30 pretty much since the 7.3. That being said, it wasn’t readily available and people have gone hundreds of thousands and in some cases millions of miles on 15w-40 in some cases. Now their new 6.7 comes factory filled with 10w-30 Diesel engine oil. 15w-40 isn’t recommended in temps below 20 degrees. That being said this quite interesting coming from Cummins where a lot of people have always used 15w-40 in their engines. Going to be interesting to see more information pertaining to this If it’s ever released as to why. Their reasoning is a little interesting to me, being as most 15w-40’s shear out to about a 10w-30 by the end of their useable life. Maybe this is the reasoning, due to the shearing it may cause deposits that don’t agree with the valvetrain


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[Captainmal]

btw, Cap you might want to reread your note and correct it.

All the best,

"Service bulletin on oil selection for Cummins engines. The last part is of importance to both earlier ( pre-'19) and newer (post '18) engines."

What should I correct? The pre-'19 engines are from 2018 and earlier. They can use the 15-40...according to the bulletin. The post '18's are from 2019 - 2021. They are NOT to use that 15-40W oil, according to the bulletin.

Thought I read the bulletin correctly. Beats me. Just trying to add information on the issue to this forum. It sure is "dead" on the HD topic section, partly because there is really not much to talk about as the trucks just seem to soldier on with few major issues. If it were not for the CP4 discussions there would be little to have any forum contribution topics other than transmission, tires, add-ons, tuning, DEF etc. Seems the Cummins owners have no serious motivation to post trouble as there is little trouble to talk about.

Now maybe we could talk about the 800 miles or so per gallon of DEF consumption? Some of the HD Cummins with the new hydraulic valve engine have now gone over 100K miles with few to no issues. Just the way it is.

 

[howie12]

Not sure where the 0W-40 reference is coming from but the new 6.7 uses either 10W-30 or 5W-40. One big difference is the new 6.7 has hydraulic lifters which needs the oil to keep them pumped up correctly. Cummins has approved 5W-40 for years and lots of oems are going to 10W-30 now for fuel economy.

yes, that was my error. I should have typed 5w40 but the point I was trying to make is the same. My apologies. I have quoted the relevant portions from the TSB below

For all trucks, regardless of model year, located in areas where the ambient temperatures routinely fall below 0°F (-18°C) during the winter, it is required to use 5W-40 synthetic engine oil that meets US Material Standard MS-10902, and API CJ-4. Oils that meet this requirement can be found through Mopar, as well as Shell in the Rotella and the Rimula families. Although this grade of oil is required in colder climate areas, it is also safe to use during the summer months, and in warmer climates as well.

 

[howie12]

"Service bulletin on oil selection for Cummins engines. The last part is of importance to both earlier ( pre-'19) and newer (post '18) engines."

What should I correct? The pre-'19 engines are from 2018 and earlier. They can use the 15-40...according to the bulletin. The post '18's are from 2019 - 2021. They are NOT to use that 15-40W oil, according to the bulletin.

Thought I read the bulletin correctly. Beats me. Just trying to add information on the issue to this forum. It sure is "dead" on the HD topic section, partly because there is really not much to talk about as the trucks just seem to soldier on with few major issues. If it were not for the CP4 discussions there would be little to have any forum contribution topics other than transmission, tires, add-ons, tuning, DEF etc. Seems the Cummins owners have no serious motivation to post trouble as there is little trouble to talk about.

Now maybe we could talk about the 800 miles or so per gallon of DEF consumption? Some of the HD Cummins with the new hydraulic valve engine have now gone over 100K miles with few to no issues. Just the way it is.

You are absolutely correct Cap. I am not sure what was wrong with my brain that night. Perhaps it was the cold weather, the long snowmobile ride prior to looking at the forum and the third brandy. Shame on me. Jeez I hate when I do this!

 

[r3gill]

To be honest nothing was wrong with the older 2018 cummins 6.7s. The older 6.7s still had alot of potential for more hp/torque. Don't know why cummins has tried opening a new can of worms.

 

[Captainmal]

To be honest nothing was wrong with the older 2018 cummins 6.7s. The older 6.7s still had alot of potential for more hp/torque. Don't know why cummins has tried opening a new can of worms.

The older, solid lifter, Cummins was a classic motor with a long reputation for reliability. It is a bit loud in operation and does need some periodic valve adjustments. Kind of "old school" in design with block and other components. That just may be a good thing.

New motor seems fine and quiet. the change to the CP4 pump was a mistake and the 2021's are back to a version of the more reliable CP3. New motor arrangement easily puts out more power but that is a mute point as maybe there already is too much power for most users. My take is the new motor is fine.

 

[MAS]

Too much power.... say it aint so capt!

 

[Captainmal]

Too much power.... say it aint so capt!

NO.

I think the new Cummins is too much power for my needs. When I bought the Ecodiesel it was because I did not need or want a giant 6.7L engine. That engine, to me, would be too large for good fuel economy and have way more power than I would need.

That is the case today.

If the Ecodiesel were more reliable I would have kept it. To me that was near the power of my old 5.9 Cummins but had that hideous V6 design and was a bit too small and busy for me. I wanted and still would want an in-line diesel engine about 4.5-5 L with NO TURBO and reasonable power to haul 8-9K successfully. That fits the needs for most people I see with pickups. It sure would fit my needs. My current hydraulic valve Cummins struggles to get me 21 mpg. Under light tow it drops to 18 mpg. With my side-by-side on my new 10 ft. trailer the profile and windshield has a lot of wind resistance. I do 15 mpg towing on the interstate. I think that sucks.

The engine is too big for my wants and needs. The other options - V8 engines of about the same size - are worse by design and operation for me. The little 3.0 engines are too complex and the 2.8L in-line GM engine is not big enough (but the best design).

There is nothing made today that fits the diesel wants of a causal owner that tows recreational trailers that are not giant mobile homes. Just because i can does not make my engine the right one.