In the paper owners manual diesel supplement it states "in ambient temps below 0 F (-18 C) SAE 5W40 SYNTHETIC engine oil that meets Chrysler maintenance standards MS-10902 and API CJ-4 engine oil category is required.

It then goes on to state "Failure to use SAE 5W-40 SYNTHETIC engine oil in ambient temp below 0 F (-18 C) could result in severe engine damage."

Can't get much more direct than that. I actually did my first oil change with 15W40 full synthetic before I got the paper manual then I read this and had to change oil again after only a couple of thousand KM.

 

Another possible misnomer of mine, but I also thought that because this engine has tighter design tolerances that regardless if you chose to delete or not, you still wouldn't want to run a higher ash content oil because of the valves? I guess the type of ash content would determine that as well (calcium vs magnesium).

 

Exactly! But remember, it is the 15W or 5W that determines the cold protection properties. If you are using a conventional 15W, I wouldn't even go that low before changing the oil. A good way to test that is to take a half jar of conventional and half jar of synthetic 15W and put them in the freezer set around 20 degrees for a few hours. This will make one reconsider using conventional oil. I have seen vehicles during the winter in Montana not start because of using conventional oil (can't get the engine to turn over fast enough) and those that were using a synthetic oil would start just fine. We had to push a guys truck into one of the bays at the fire dept and let it sit for a couple hours before it turned over fast enough to start.

 

Nothing changed on the valves, tappets, cam, etc... really a high Zinc oil is better for them.

 

Good to know! Thanks!

 

OK Guy's, thanks for all the oil facts. It all has helped me understand some facts I didnt know about oils. One thing I still confused on. I have done the the full deletes, what oil should I be using CI? CJ? also what does those leters mean? I dont care how much it cost but what is going to protect my motor the best. I live outside Sandy Oregon in the foot hills of Mt Hood. It gets cold in the winters but not that cold. Maybe lows around the low teens.

Thannks for all your time and help.

 

Okay, I am a big fan of AMSOIL and have ran it in all of my vehicles front to back since 2002 with ZERO issues so I will be biased towards AMSOIL oils. My recommendation would be this: It seems some of the more knowledgeable guys are recommending to run the CI-4 oil with deletes. After doing more research, I think I may just agree with them due to the fact that having a higher ash content (thus a higher TBN) can be more beneficial for the engine. So with that in mind, I would try the AMSOIL Synthetic Diesel & Marine Oil 15W-40 (AME). It for pre-2007 diesels, but since we have done deletes...I guess we can say we meet those requirements.

However, I wouldn't shy away from trying the Amsoil Synthetic 5W-40 Premium Diesel Oil (DEO). It is a CJ-4 oil, however, even though it has a slightly lower TBN, it doesn't make it a bad oil for a deleted or even a pre-2007 diesel engine. In fact, eliminating the regens the TBN would more than likely go down at the same rate as the previous oil I mentioned, if not even at a slower rate due to the premium base stock and chemicals used in it to counter the detrimental affects of regens. I am currently running this oil and will see about picking up an oil sample kit this week from the distribution center (if they stock them). I am about 100 miles shy of 3K miles on this oil change, so now would be a perfect time. I will easily put at least 20K miles/yr on my truck so it would be perfect to do some comparisons. I plan on changing the oil again in April (or sooner based on the oil sample) and when I do, I will run the 15W-40 CI-4 oil to see what difference it makes (other than probably decrease my gas mileage).

If you choose to run AMSOIL, research both of those oils. IMHO the only difference between the two would be that the 15W-40 is $0.85 cheaper/quart (Retail) than the the 5W-40. One last thing, I know you said it gets cold, but not that cold where you are at, if you choose to run the 15W-40, it remains fluid down to -44deg F, so I wouldn't worry too much about the "winter" side of the two oils and more about what you feel will meet your needs more.

Josh

 

I agree, if you want to run a great synthetic CI-4 oil then the AME is the way to go with the EaO80 or ELF7349 filter for a full flow.