I have been wanting to switch from dino oil to synthetic oil and have narrowed it down to Amsoil, but which one? I have a 2006 5.9L CTD and I have read that it is best to stick with a API CI-4+ and to stay away from the CJ-4 oils. Is this correct? I have looked at the Amsoil products and came up with 3 different ones. 1. (AME) 15W-40 Synthetic Heavy Duty Diesel & Marine Motor Oil (CI-4+) 2. (DEO) 5W-40 Synthetic Premium Diesel Motor Oil (CJ-4) 3. (HDD) Series 3000 5W-30 Synthetic Heavy Duty Diesel Motor Oil (CI-4+).

So if my prevoius statement was correct about not using a CJ-4 oil then I should stay away from the DEO, correct? And now that narrows it down to 2, the AME and the HDD. I live in Durango Colorado and this last winter we had 10-20 below 0 temps with a high in the 20's above 0. In the summer months we see highs in the 90's. I really only plan on changing my oil once per year as I have only 12,700 miles on the truck and have owned it new since Oct of 2006. So which oil is best for me? And if I plan on only changing my oil once per year do I need a bypass or should I use a Amsoil filter or since I have like 4 Fleetguard Stratapore filters left, use up them? Thanks for your imput.

 

I say 15w-40 Diesel/Marine is your best bet. And its best to use AmsOil Ea filters with the Amsoil oil. It will help extend your drain intervals even further.

And yes, adding a bypass will extend intervals. AmsOil sells a great dual-bypass setup. Most most people who run a dual by-pass never change their oil, they just change filters and top it off.

 

This is what is currently in the garage waiting to be poured in.

I also will be using the Ea series oil filters.

Thankfully, my local NAPA store stocks both.

 

I would go with the 5W-40 Synthetic Premium Diesel Motor Oil. I use the same wait but in Schaeffers with good luck. I am also using a Fleetgaurd filter with FS2500 filter. Works great and stays clean.

 

I use the 15/40 Amsoil and have had good luck with it so far. Pushing 100k I change the filter every 5k and make up oil. Change the oil every 25-30k depending on where and what is going on with my schedule.

Good Luck, Jeff

 

I use the Series 3000 and the bypass filter setup, works good for me.

 

I use the 5w30 HDD with Fleetguard Stratapore oil filter year round and now only do a full oil change once a year. I do change out the filter at 6 months or 7500 miles just to make me happy along with a UOA at every filter change to cover my back side for warranty. Our temps get down to -30 below zero in the winter and up to 100 in the summer along with 70-100% humidity.

 

HDD.... best oil Amsoil makes....

 

HDD 15w-40 Diesel marine oil. Very good stuff. That's what I use.

 

I thought we 5.9L guys need to stay away from the CJ-4 oils. It looks like most are using the (AME) Heavy Duty Diesel & Marine from the postings so far. Would I be ok changing this type of oil once per year and changing my Fleetguard Stratapore filter every six months?

 

HDD is the 5w-30, the Marine oil is AME

CJ-4 oil doesn't have the standard extended drain interval like the CI-4's do... I would run the HDD or AME... I would also run the amsoil filters, they are better.

 

I'd recommend the AME 15W-40, and the EAO-80 oil filter. This combo will be good for up to 15,000 miles, or one year, which would be in your case.

If you feel comfortable with using a Fleetguard filter and changing it every six months that's fine. Just remember to top off the oil when you do change.

The Premium 5W-40 CJ-4 oil can be used, but shouldn't be extended past 7,500 miles. If you wanted to extend the drain intervals with this oil, you should start an oil analysis program. At this time, we've seen good numbers up to the 10,000 miles. After that, the numbers seem to drop. These are also from the new 6.7, not the older 5.9 Cummins.

Hope this helps
Paul

 

With what I've come up with over the yrs , never use anything less than 10-??w weight , anything less is too thin for the average , I have use 15-40w Rottella here in MN. at colder than -20*F not plugged in , so unless it colder longer .
The reason why is that you getting less lube protection from the thinner oil , this is from being in the auto repair bis for a few decades and reading lots of articals and talking to oil analysis lab techs , away from the lab where they have ears , but at watering hole .
I use the Amsoil 15-40 marine & dual by pass , change by analysis only .

 

Since you asked, my choice would be none of them...run Rotella, Delo, or Delvac instead...

 

Well that just does not make sense to pay $1.50 more per gallon for the Premium 5W-40 CJ-4 oil over the HD Diesel & Marine CI-4+ oil, especially if you get twice the mileage out of the oil.