Synthetic oil weight for Cummins ISB 6.7 litre engine?

[gordonsick]

I'd like to run synthetic oil in my Cummins ISB 6.7. Cummins says you can use synthetic but it also specifies 15W40 oil. At Canadian Tire I can get synthetic Mobil 1 or Rotella diesel oils that meet the Cummins spec except that they are 5W40 or 0W40. Does anybody know of a Cummins statement on this?

[SKnight]

I'm not aware of a Cummins statement but I've run Mobil Delvac 1 5W40 in my truck for 13 years now with no complaints.

[Kenny kustom]

This. Year round.
Check out genos garage.
They sell filter packs. Fleet guard.
Oil and fuel filters. Fuel filters get done every second oil change.


2015 RAM 3500 CCSB CUMMINS
2016 Sabre 36QBOK

[Paulie Boy]

Rotella 15W40


Paul

[Kenny kustom]

You mention " Canuck tire"
So I would guess... Canadian.
Then I must recommend the 5w40

I can recall last winter, my truck displaying oil coolant and trans temp, all in the -30c range.
Synthetic.

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[gordonsick]

Yes, I'm Canadian, but I don't plan winter driving.

I suspect that I'm OK by lowering the lower end of the weight from 15W to 5 W or 0W, since that only affects the engine when cold, and it might help oil flow when starting up.

It is important to keep the upper end at 40, since that is what the engine does when hot.

But, I'd really like an authoritative reference from Cummins to confirm, since it would affect my warranty.

The do suggest not using synthetic until after the first oil change.

[Kenny kustom]

Same as my last truck.
Dino oil till 5km.
Then rotella 5w40.

That's also what we used when I worked at Chrysler.



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[Kenny kustom]

If you read the manual it will tell you what i am saying.




2015 RAM 3500 CCSB CUMMINS
2016 Sabre 36QBOK

[gordonsick]

Originally Posted by Kenny kustom

If you read the manual it will tell you what i am saying.

2015 RAM 3500 CCSB CUMMINS
2016 Sabre 36QBOK

Thanks Kenny. I don't have a Ram truck, which is why I don't have that manual. I've got the 6.7l engine in my Berkshire motorhome.

I think the two 6.7l engines are basically the same, so it does give me some comfort in using the 5W40.

–cheers, Gordon

[Kenny kustom]

That's the CUMMINS supplement manual.
You should have that one.


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[I-RV]

While at a Cummins factory shop, I purchased Valvoline Premium Blue Extreme, Full Synthetic 5W40. It even has a Cummins endorsed seal on it. Cummins highly endorses it, but I'm sure that other brands will do.
Hank

[gordonsick]

Kenny,
Thanks for sending me to the Cummins manual. I thought I had read it, but I hadn't! It provides similar information to the RAM manual.

Just for the record, my manual is Owners Manual ISB6.7 CM2350 B101. Page V-22 suggests that any revisions are available in Bulletin 3810340. The manual does specify the following oil API gravities as being acceptable:
All Seasons (5°F and up): Either 5W40 or 15W40
All Seasons (-5°F to 115°F) 10W30
Winter Conditions (-5°F to 70°F) 10W30
Winter Conditions (-10°F to 70°F) 5W30
Arctic Conditions (32°F and below) 0W30

Interestingly, this means that it recommends 10W30 over 5W40 for temperatures that drop to -5°F. I had thought that you only had to worry about the low end of the viscosity range for cold temperatures, but they say that is wrong.

Also, it says nothing about 0W40, which is an available synthetic oil.

Page V-21 states that oil must meet Cummins Engineering Standard CES 20081, which is apparently stricter than the American Petroleum Institute API CJ-4/SL.




2015 Berkshire 34QS
2005 Acura EL aka Honda Civic

[gordonsick]

Since Mobil 1 Delvac is a 0W40, it is not strictly within the list of acceptable Cummins SAE weights.

But, two oils are available to us Canadians, that I can see:
Shell Rotella T6, as well as Motomaster Formula 1 Synthetic, 5W-40 are CJ-4 rated and meet Cummins CES 20081


2015 Berkshire 34QS
2005 Acura EL aka Honda Civic

[Kenny kustom]

If you are never winter driving it, stick with 15w40.


2015 RAM 3500 CCSB CUMMINS
2016 Sabre 36QBOK

[gordonsick]

Kenny,
But, if one wants to use synthetic oil, they have to go to 5W40 or 0W40, given the choices I have at Canadian Tire. If I look long enough, I might find a synthetic 15W40 or 10W40 that meets the Cummins CES spec, but I like the discounts at my local store.


2015 Berkshire 34QS
2005 Acura EL aka Honda Civic

[gordonsick]

One more thing from the Cummins ISB6.7 manual.

Page 1-8 talks about fuel dilution of lubricating oil becoming a problem if one operates the engine at low idle for long periods with the engine coolant below 160°F. That is not likely a problem that I would have.
The manual goes on to say on page V-22 that "Multivisosity oils rated 0W-30 do not offer the same level of protection against fuel dilution as to higher multigrade oils.


2015 Berkshire 34QS
2005 Acura EL aka Honda Civic

[gordonsick]

The Cummins oil bulletin that I mentioned earlier is available without a login at
http://www.granlydiesel.dk/fileadmin...il_3810340.pdf


2015 Berkshire 34QS
2005 Acura EL aka Honda Civic

[ervinglobal]

Originally Posted by gordonsick

I'd like to run synthetic oil in my Cummins ISB 6.7. Cummins says you can use synthetic but it also specifies 15W40 oil. At Canadian Tire I can get synthetic Mobil 1 or Rotella diesel oils that meet the Cummins spec except that they are 5W40 or 0W40. Does anybody know of a Cummins statement on this?

I live in Calgary. I always used 5W40 Amsoil. I had many diesel trucks Ford, GM Cummins I just sold my 2014 6.7l Cummins Dodge Ram. I find this oil is the best for me all year around. You can order it on line and delivered to your house. Now I have a 9.3L Maxxforce in our motor home. I just had the first oil change I feel a difference in sound and performance when it starting in colder climate. You will not be sorry to switch. It cost a little more but so as the mechanic shop if something brake down.
Cheers

[Kenny kustom]

Originally Posted by gordonsick

Kenny,
But, if one wants to use synthetic oil, they have to go to 5W40 or 0W40, given the choices I have at Canadian Tire. If I look long enough, I might find a synthetic 15W40 or 10W40 that meets the Cummins CES spec, but I like the discounts at my local store.


2015 Berkshire 34QS
2005 Acura EL aka Honda Civic

I run the rotella 5w40 year round.
Catch it when it's on sale and stock up.
Filters from genos.
Easy peasy.


2015 RAM 3500 CCSB CUMMINS
2016 Sabre 36QBOK

[baddmann]

I run Rotella T6 in everything. Jeep, Jet Skis, Berk, etc. It is one of the better oils on the market. If you look at other forums, it is debated quite frequently. I think the main issue with oil is changing it during proper intervals.