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Topic: What oil for Cummins M-11? (Read 3730 times) previous topic - next topic

What oil for Cummins M-11?

What oil should I used in a Cummins M-11?  The manual states 15-40 API CE/SG or CF4, but according to Dieselnet.com

"By 2012, all service categories except CH-4, CI-4 and CJ-4 were obsolete and a new one was under development. A common reason for the obsolescence of the older categories is a lack or facilities and parts to run some of the key engine tests."

I did not see anything in the backward compatibility chart for CE/SG, but CF-4 references CI-4 and CI-4 plus.

Second question, where do you buy your oil and in what size containers?  I presume 1 gallon containers are easiest to handle.
40ft 1997 U320

Re: What oil for Cummins M-11?

Reply #1
Many of us use synthetic oil, sent you a PM,Amsoil is a good one,I use the 21/2 gallon container.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: What oil for Cummins M-11?

Reply #2
Costco Delo 400 15/40 with the CK rating is what I buy.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: What oil for Cummins M-11?

Reply #3
I use Delvac super 1300 15/40 in my Cummins and Detroit's.. Wall Mart 12.47 gallon.. Rotella 15/40 used for decades.. both good oil and I've got a million plus miles on different engines with both brands. I believe the super 1300 is called a semi synthetic.. same oil in generator.
Dub McBride 1996 270

Re: What oil for Cummins M-11?

Reply #4
Definitely 15W-40. I prefer Valvoline Premium Blue but there are several excellent choices.
David and Carolyn Osborn
1995 U320C SE 40' Build 4726 Feb 1995
FMCA 147762
Motorcade 17186

Re: What oil for Cummins M-11?

Reply #5
15-40 in most any brand is good oil these days
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: What oil for Cummins M-11?

Reply #6
15-40 in most any brand is good oil these days
It must be able to meet your engine manufacturer's  standards, most do not.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: What oil for Cummins M-11?

Reply #7
Yes, the new oil designation for all but the newest engines is CK-4.  It is backwards compatible with all diesel engines before those with DEF.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: What oil for Cummins M-11?

Reply #8
I use Rotela T-6 synthetic. in all my diesel engines. Good protection, flows better when cold so its easier for the engine to turn over and to get oil up into engine quicker.
1995 U320C SE 40'
Jeep 4x4 Commander - Limited - Hemi
"The Pack"  Yogi and Diesel our Airedales -  Charlie our Boxer/Akita mix. Gone but NEVER forgotten Jake our yellow Lab.
NRA Law Enforcement Firearms instructor - Handgun/shotgun
Regional Firearms instructor for national Armored Transp. Co.

Re: What oil for Cummins M-11?

Reply #9
I use Rotela T-6 synthetic. in all my diesel engines. Good protection, flows better when cold so its easier for the engine to turn over and to get oil up into engine quicker.
What grade?
15w40?
5w40?
Tim Dianics
Pam Sapienza
Vader PupZilla Labrador Canine Beast (AKA Pup)
Columbia, MO
1996 U320 4000
2021 Jeep Gladiator, Diesel

Re: What oil for Cummins M-11?

Reply #10
Not all oils are high detergent.

Cummins shop installed Delo 400 LE in our m11
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: What oil for Cummins M-11?

Reply #11
Delo 400 15-40 or Shell Rotella T 15-40. Both meet the proper CK-4 specs.

Sure, there are other good oils, but, both meet your engines mil-specs AND (big AND) are available in most every Walmart and auto parts house in N America.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020


Re: What oil for Cummins M-11?

Reply #13
Promo excludes Advance, AutoZone, Carquest, Costco, Mendards, NAPA, O'Reilly, Pep Boys, Sams Club or Walmart....pretty much all of the places I shop!

40ft 1997 U320

Re: What oil for Cummins M-11?

Reply #14
Costco usually matches the promo prices.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: What oil for Cummins M-11?

Reply #15
Use Tractor Supply here in Texas. They will have it on sale again soon.
1999 U270 40 #5518
USN. USPS.


Re: What oil for Cummins M-11?

Reply #17

I use the 5-40 T-6.
1995 U320C SE 40'
Jeep 4x4 Commander - Limited - Hemi
"The Pack"  Yogi and Diesel our Airedales -  Charlie our Boxer/Akita mix. Gone but NEVER forgotten Jake our yellow Lab.
NRA Law Enforcement Firearms instructor - Handgun/shotgun
Regional Firearms instructor for national Armored Transp. Co.


Re: What oil for Cummins M-11?

Reply #19
Low viscosity , ie 0 or 5 weight oil  are necessary in computer controlled car engines because the computer immediately brings the engine rpm to 1500 rpm or higher. The most common failure is camshaft related. In most car engines the aluminum cylinder head has no bushings,  just the aluminum in the head. The camshaft of course is steel. At cooler temperatures the 10-30 oil takes too long to get to the camshaft,  resulting in cylinders head damage.
I use 15 40, primarily because ambient temperatures in some areas are high...
Will 0 40 harm your Cummings,  I doubt it.
But the manufacture calls for 15-40, so that's probably what a person should use.

Safe Travels,
Dave
2001 U320 40ft
Build #5867
2003 Tracker
VE7DOD

Re: What oil for Cummins M-11?

Reply #20
Why do you use 5W-40? Wasn't your engine designed to use 15W-40?
Engines are "designed" to be run with oil that meets certain specifications.  From there one chooses a viscosity to cover the temperature range that the engine will be operated in.  Rotella T6 5W40 might be overkill for engines that are never started in temps below 50F, but the only possible harm in that situation is to a person's wallet due to the higher cost of the oil.
Dave and Kelli
1997 U295 40' Build #5188 CSGI
1995 U240 36' Build #4621 SBID-SOLD
2006 Jeep Wrangler Rubicon

Re: What oil for Cummins M-11?

Reply #21
Engines are "designed" to be run with oil that meets certain specifications.  From there one chooses a viscosity to cover the temperature range that the engine will be operated in.  Oil.Rotella T6 5W40 might be overkill for engines that are never started in temps below 50F, but the only possible harm in that situation is to a person's wallet due to the higher cost of the oil.

As far as I know the Cummins M11 was designed to operate on 15W-40 and not on 5W-40 oil. That's why it seems better to me to use 15W-40 in it.
David and Carolyn Osborn
1995 U320C SE 40' Build 4726 Feb 1995
FMCA 147762
Motorcade 17186

Re: What oil for Cummins M-11?

Reply #22
Our local high volume Cummins dealer only uses the delo 400 LE 15-40
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: What oil for Cummins M-11?

Reply #23
Why do you use 5W-40? Wasn't your engine designed to use 15W-40?

I live in Chicago.
Most of my travels take me into the northern part of this country. Most months of the year find morning and evening temps. below 50 degrees and much lower.
Most wear on engines and mechanical parts occur when the engine is cold and continues until the engine warms up. With the M11 and its large oil and cooling capacity it takes a lot of time for the engine to reach operating temp.
As the oil heats the viscosity moves up to the 40 weight range same as the 15-40 oil. The synthetic also flows better than "dino" oil at low temps.
The combo of Synthetic and 5w makes me feel better at start up for MY situation.
This is why I chose the 5-40 synthetic.
1995 U320C SE 40'
Jeep 4x4 Commander - Limited - Hemi
"The Pack"  Yogi and Diesel our Airedales -  Charlie our Boxer/Akita mix. Gone but NEVER forgotten Jake our yellow Lab.
NRA Law Enforcement Firearms instructor - Handgun/shotgun
Regional Firearms instructor for national Armored Transp. Co.