API Engine Oil Ratings

[SunnyJim]

Amsoil does make diesel oils for before and after the ? date; which specs use by one type before and another type after the date noted in their specifications. I seem to remember it was before and after 2007 ? but it could easily be a different date/year.
IMHO, it has to do with emissions and ULSD, additives and politics, and engine wear due to lower amounts of lubricants in the ULSD available now.
Whatever the reasons, right or wrong, politically motivated or not it is no easy task figuring out what to use -
I am about to do my 50 hour service at about 85+ hours and switch to Amsoil synthetic for most recent diesels engines.
I am sure it will work well for my tractor.
Good luck to the rest of you- and keep asking the questions of the manufacturers- to make them say what it is they want us to use to keep warranties valid and honored.

CM

I went with Amsoil AME in my '08 CK25 since it does not have EGR or DPF. I also use ACD in some of my equipment. Are you going to use DEO 5w-40 or DME 15W-40? Being in VT I would choose the DEO for cold weather starting.

AMSOIL - Synthetic Diesel & Marine Motor Oil SAE 15W-40 (AME)
AMSOIL - Synthetic 10W-30/SAE 30 Heavy Duty Diesel Oil (ACD)

 

[WH401]

One thing to remember is that because of Amsoil's synthetic properties, the difference in how a 15w-40 flows compared to a 5-40 in the winter isn't really an issue. While it does get much colder in VT, I don't think you'll have a problem at all with the Amsoil 15w-40. I have run that in a 7.3 Ford Excursion for the past two years, and noticed a big difference in the flow of the oil when it was started from a dead cold state (around 15 - 20 degrees F). The 5w-40 would probably flow slightly better, but I don't think it would be a big enough difference to be worth changing from a 15w-40. Personally, I would run the 15w-40, but both are very good oils.

 

[SunnyJim]

Its going to depend on how cold it will be when you are starting the tractor and how much you use it in the cold. In NC its really not cold enough to matter, the coldest it got last winter was 18F I believe. If you are starting below 0F then you will notice a bit more difference with each oil.

For truly cold starts I would rank them thinnest to thickest for 40 weights.
1. DOE
2. AME
3. DME
4. PCO

Any of them are very good of course.

You can Graph them all and adjust your temperature to the lowest C you are expecting to compare. All you need is the 40c and 100c viscosities. My lowest temp is 18F = -8c rounded.

Fahrenheit to Celsius Converter

 

[Coyote machine]

I'm using the 15-40 diesel oil, NOT the marine diesel but the CI-4 stuff. I expect no problems 'cause it will be stored in a radiant heated floor barn and has a block heater just in case it gets stuck outside, and in a worst case scenario I can take my portable generator and power the heater.
If there is anything beyond that I guess I'll be stuck!