5w/40 Amsoil instead of 15w/40 Amsoil

[LwnmwnMan2]

How big of an issue is going to be using 5w/40 in my Cummins this summer instead of 15w/40?

Remember, there's a trailer hooked to this truck 7 days / week pulling a payload of 9k lbs, +/-.

Thanks.

[theoilman]

What year is your engine? (A 5.9L Cummins is a 2006 or earlier model engine, A 6.7L Cummins is a 2007 or newer model engine. Yes, the engine year, not the truck year - many 2007s had 2006 engines.) How many miles on the engine?

The 5W-40 diesel oil is CJ4 for ultra-low emission engines. Can be used for earlier.

Which 15W-40 - they all (currently) are for CI4+ 2006 and earlier engines - NOT for ultra-low emission engines.

And to add to more questions, the CJ4 spec AMSOIL diesel oils are going change soon.

Need more info to give you an accurate answer.

[LwnmwnMan2]

Okay, I bought the 5w/40 for my 2007 Dodge 6.7, which I read off of Amsoil's HSOforum to use the 5w/40, but after I got home, I read the book in the truck and it says only 15w/40.

Same thing with the 2006 5.9, book says only 15w/40.

In June I need to head back to Superior and get another shipment of oil, and I'm sure if I explained what happened I could get a case of 15w/40 in place of the 5w/40, but at the same time, I've got another 2006 5.9 that needs an oil change.

46k miles on the truck,

[theoilman]

First and most important is the API Service Rating. An Ultra-low emission diesel engine requires CJ4. Never use a CI4 or CI4+ that does not also have a CJ4 rating in an ultra-low engine. The additives used in the CI4 will definitely harm the catalytic converter and the exhause particulate filter.

The viscosity 'preferrences' and 'allowed or ok' information that I have for the Dodge / Cummins 6.7 Ultra-low engine - 15W-40 preferred for above 0 deg F; 5W-40 ok for all temperatures but if you use 5W-40 it must be synthetic.

The second number is always the most important, the viscosity at 'normal operating conditions.'

The first number is the viscosity cold (actually measured at +40 deg). The lower the number, the lower the 'cold cranking' performance, usually better. Petroleum oil with too low a first number or too great a spread between them will have high volatility. This is not a problem with AMSOIL.

For now the only oil available from AMSOIL for the CJ4 ultra-low engines is the 5W-40 product code DEO. The current DEO 5W-40 carries a service life recommendation from AMSOIL of use only for the oem maximum recommended interval, do not go extended beyond that unless you use 'used oil analysis.'

However, this is going to change in the very near future. AMSOIL has an upgrade in formulation for the 5W-40 coming with a much longer extended interval available. Also a new 15W-40 in the CJ4 spec also will be available. There is a dealer training webinar April 2 and I expect to find out release information and more info then.

If it were mine I would use the 5W-40 - there should be absolutely no problem. The 5W-40 DEO is AMSOIL's first (and only) choice for your truck - and the AMSOIL warranty will definitely cover you.

Personally, in my 2006 Sprinter 1 ton (5 cyl Mercedes 2.7L diesel, but not an ultra-low engine) I use the AMSOIL 5W-30 HDD CI4+ high performance diesel oil. I have no oil consumption nor any other problems. I drive 24,000 miles per year, in Florida, 8000 lbs normal total vehicle weight, tow a 3000 lb trailer 2 or 3 days a month, and have been at max with 10,000 vehicle and load plus 3000 lb trailer (or more) a few times.

Send me your e-mail address and I will be glad to pass the information on to you then (mine is below, I do not sell or trade info with anyone).

[theoilman]

The AMSOIL CJ4 oils for ultra-low emission 2007 and up have now been changed and upgraded:

There are now 2:

5W-40 prod. code DEO (upgraded April 1) and

15W-40 prod. code DME (new April 1)

These are supposed to be in all the distribution centers and now available. They carry an up to 3 times the OEM recommended interval service life.