mrmcsd

Hello Friends. I went to the dealer the other day to get my oil changed because they had a special. I told them that I wanted full synthetic only. Luckily I watched the tech because he was going to use 10-30 standard conventional. Anyway when I told him synthectic only, he proceeded to use Mobil 1 10-30 (green lable). I know by excperience that I can use this type in my gas motors, but is it ok for the diesel? I really did'nt question the tech at the time. But now I am thinking about it. I lke to go at least a year between oil changes, and dont want to damage my engine. Any educated input will be greatly appreciated. Thank You

D45

Personally, I would not put 10W-30 Mobil 1 in my truck

AkitaSumo

This one looks like Mobil 1's for diesels...

http://www.mobiloil.com/USA-English/...uck_5W-40.aspx

Time for a trip back to the dealer?

Monty

Tell them to only put CJ4 rated oil in your truck. Mobil Delvac Syn, Rotella Syn, Mobil 1 5w40 Turbo Diesel syn come to mind.

bigwheels94

Cummins requires 15W40 oil in all thier engines.

Monty

They dont "require" you to run 15w40. However, they do require you to run an approved CES20078 (CI4) or CES 20081(CJ4) approved oil. There is nothing wrong with running an approved synthetic lubricant, or, a CJ4 10w30 or 40 for colder climates such as Rotella T.

capnp72

5W40 is the recommended viscosity for synthetic oil. If you are going to use Mobil 1, you should use 5W40.

RyeThomas

Correct sir

Ive used that oil (mobil 1 5W40) for many miles at high horespower and with twin turbos, (some say not to use synthetic with turbo aplications). Not one issue and still going strong. I also use Mobil 1 synthetic in my SRT-8, 0-W40 and my dads insane S-65 Bi-turbo Benz says only use mobil 1 synthetic. So get the right viscosity and you will be just fine .

DieselBoy20

Is your truck a 6.7 or a 5.9? If its still a 5.9 then I would use a CI4 rated oil and stay away from CJ4. The CJ4 stuff is lacking some additives that the CI4 oil for our trucks need. If you look around you will find CI4 oil out there. John Deere still makes it and so does the Valvoline Blue. Use a 15w40 also. Lots of guys use 0w40 all year round too but I would only use it during winter months if it was me.

PourinDiesel

Someone's been doing their homework. Good post, very informative with good info.

DBLR

If you have a low mileage 2005 or newer engine then you can use 5w30 HDD oil year round so long as it meets CI-4+ spec's.

tool

I've been running the Mobil1 5w-40 Synthetic for the last few changes. Haven't had it sampled yet though.

CRXsi

Why would you not recommend running 0W40 during summer months? Check out the viscosity charts on something like Esso extra XD-3:

Esso Extra XD-3 0W40

and also Mobil 1 turbo diesel truck 5W40:

Mobil 1 turbo diesel truck 5W40

and see the viscosity indexes for yourself if the reason is because you think there is a viscosity issue....

Also keep in mind I would pay approx $38 a jug for Mobil and I only pay $22 a jug for Esso XD-3. XD-3 is a true group IV synthetic...Mobil used to be but rumour has it the newer formulations are only group III, I have no proof if Mobil is or not.

Roperteacher

I have a 5.9 and was told by cummins it was fine to run the CJ oils, you just can't go as LONG with them. I go every 5,000 and have great UOA's come back with the Premium blue CJ.

DieselBoy20

I think tons of guys do run a 0w40 during summer months and I know lots of the heavy equipment i run especially do but I wouldn't do it in my truck, everyone has there own opinions on that. I have also been told by a wise mechanic who really approves John Deere Plus 50 15w40 in our trucks, they have powerful detergents that keep everything spotless. So thats what I run in my truck right now. I think the CJ4 stuff is fine but also have been told to keep running CI4 oil in our 5.9L as long as they keep making it.