Rotella T6 for Duramax LML. What flavour?

[weebl]

I am planning on grabbing a pail of T6 after work today to do an oil change on my LML. Since getting the truck a couple of years ago, I have used Delo full synthetic 5W-40 and Rotella T6 5W-40.

I am located in Edmonton, Canada.

The truck will normally see 98% of it's use from spring to fall each year, with temperatures not likely below freezing at the coldest, but could see quite high ambient temperatures. It will be used to tow a fifth wheel trailer, and since getting the truck, I've done a cross country trip one summer, and a trip to California the second summer. Definitely will be climbing mountains while towing in high ambient summer temperatures.

I also want to be able to use the truck in the winter, if needed. During the winter season, it is usually stored nowhere that it can be plugged in, at least for the two winters I've had it so far. Next winter will be hugely unknown where it will be parked, as a relative is selling their property where I normally park it over the winter. Winters normally are around -20C (-4F), but it is quite common to see down to -40C/F here. The first winter, I took it out maybe a couple of times on a warmer winter day (probably -10C). Last winter it was started to idle for a bit a couple of times only, and again on warmer winter days. Likely would see the same limited use this winter, but if we end up moving out of the city into the country, I could see it being used more. This scenario is a maybe.

The 5W-40 has normally served me well here, even back when I had a VW ALH which saw year-round use. But I now have the option of getting a 0W-40 T6, same price, and also in stock. In the past, when the 0W-40 was first available, it was either harder to get, or cost more, or both.

I think I know the answer, but would love to hear the rationale of others of why one is better over the other.

 

[JohnnyJohnson]

I've used Rotella 5w-40 T6 in my Duramax since about 2010 it has worked just fine for me.

 

[Virtus_Probi]

If you think you might be starting the truck at -40C, I think the 0W40 is the way to go.
Even 0WXX is only tested for cold cranking at -35C, it does get a pumpability (MRV) test at -40C (-30C/-35C for the same tests for 5WXX).
I don't know that the 5W40 would give you trouble at -40C, but 0W40 can only help at that temp if you expect to use the truck when it's so cold.

 

[weebl]

Originally Posted by Virtus_Probi
If you think you might be starting the truck at -40C, I think the 0W40 is the way to go.
Even 0WXX is only tested for cold cranking at -35C, it does get a pumpability (MRV) test at -40C (-30C/-35C for the same tests for 5WXX).
I don't know that the 5W40 would give you trouble at -40C, but 0W40 can only help at that temp if you expect to use the truck when it's so cold.


What about hot weather, though? 0W-40 would have more VII than 5W-40, so would shear stability be a concern?

 

[JohnnyJohnson]

Originally Posted by weebl
Originally Posted by Virtus_Probi
If you think you might be starting the truck at -40C, I think the 0W40 is the way to go.
Even 0WXX is only tested for cold cranking at -35C, it does get a pumpability (MRV) test at -40C (-30C/-35C for the same tests for 5WXX).
I don't know that the 5W40 would give you trouble at -40C, but 0W40 can only help at that temp if you expect to use the truck when it's so cold.


What about hot weather, though? 0W-40 would have more VII than 5W-40, so would shear stability be a concern?


I don't think so my Duramax is used primarily for towing a 14,000 pound 5th wheel that has never been a issue.

 

[dnewton3]

There are generally two issues to consider: wear and staring ability.

Data clearly shows that the Dmax engine has no preference to grade in terms a wear. I don't care if we're talking 10w-30 dino (what I ran) or PAO xW-40 (boutique syns). The wear rates for Dmax engines are incredibly low; they are some of the best wearing engines in the light-duty diesel market. So in terms of wear and longevity, grade is a non-issue. And yes, I'm including "severe" service like towing, etc. I have over 550 UOAs in my database for the Dmax, and I continue to collect them in my study. Trust me when I say that anyone's opinions are trumped by facts; the Dmax does not prefer any particular grade of diesel lube.

So the other issue to review is start-up ability. Here, thinner grades rule. If your'e concerned about cold starts below -20F, then a lube with lower vis and PP will be important. Because you're not parking near electrical aids, that not only means to block heater, but also no trickle charger. Battery strength is paramount to CI engine starting; compression engine (diesel cycle) starts must have reasonably high piston speed to generate the heat for ignition. Whereas I normally think the use of syns is a waste of money, this situation may make for reasonable consideration of a syn.

I don't know where your price threshold is ... How much do you want to spend? Also, how good is accessability to lubes? Are you way out in the boonies, or near a decent sized town?

I would recommend considering Rotella T5 in 10w-30. It's cold performance stats are nearly as good as the T6 5w-40. The T5 10w-30 is simply less expensive and gives about the same cold-start abilities. Or perhaps T6 in 5w-30? If you believe that you're going to be starting is well below -30F, then I'd recommend a PAO 5w-30 like Amsoil or Castrol's Elixion, etc. Or, Canada has some decent home-grown brand lubes as well; Duron UHP in 5w-30 and 0w-30.

My point is that using a thinner grade with a lower vis rating will protect your concerns for remote, unaided starts. Don't concern yourself with needing a 40 grade; there's no proof at all that it is "better" in a Dmax over a 30 grade. So get a 30 grade to help with the infrequent remote cold starts. I can hear your hands wringing now; "30 grade is too thin for towing". NO - it's not. Not at all.

I ran conventional Rotella 10w-30 in my Dmax for many years. I pulled my RV through the Rockies, down into the blazing hot canyons of UT and AZ during summer. I ran WOT for minutes-on-end running uphill with EGTs pegged at the OEM limit. I've ran for hours into headwinds with EGTs running between 1100 to 1300 pre-turbo. Most any pundit would tell you that a thinner oil cannot hang with a 40 grade and engine damage will result. And yet the conventional 30 grade showed absolutely no difference in wear rates compared to 40 grades. My UOAs are posted on this site for all to see.

BTW - I presume you're out of warranty, so I'd say stretch out your OCIs to get the most from your syn lube purchase. I have several UOAs that show my multi-year OCIs had no bearing on wear, either. My last UOA covered 3 years and 11k miles on that aforementioned dino Rotella 10w-30.

Go get the least expensive syn or semi-syn 30-grade you think will cover the cold start concerns and don't worry about wear rates, because the Dmax is the Honey Badger of lubes; it don't care.

 

[userfriendly]

I ran XW30s in my 06 LBZ without issue. Check out Duron 10W40 synthetic.

 

[Garak]

All of the major distributors available to you, from Shell to Imperial Oil to Petro-Canada will have a full line, including 0w-30 and/or 0w-40 HDEO options at some fairly attractive prices. It would seem that some of the distributors over the years have gotten away from charging a premium for a 0w-XX over a 5w-XX in the same HDEO line. In fact, the last time I checked, which was quite a while ago, Delvac Elite 222 0w-30 was actually cheaper than Delvac 1 ESP 5w-40.

 

[A_Harman]

If you're going to be doing starts down to -40, that sort of by definition requires a 0wXX. No other W-grade is tested down to -40 for cold pumpability.
0w30 would be my choice for such cold conditions.

 

[weebl]

Thanks. I ended up grabbing a 0W-40

 

[BoiseRob]

More important than the oil, for 2011-2016 LML's, you need to run a fuel additive to add lubricity to extend the life of your CP4.2 fuel pump. Otherwise, being out of warranty, you may be on the hook for a $9k USD complete fuel system replacement. Or better yet, start saving for one of the CP3 conversion kits.S&S is the only one that is currently CARB "50 State" compliant which keeps the OEM emission system intact. Seeing that your from "the Great White North, that may not matter to you...

https://ssdiesel.com/shop/all/lml-cp3-conversions/

 

[BrianF]

Another option is PetroCan Duron SHP 10w30 semi synthetic. I found the cost recently went up, so at the bulk dealer for small quantities of single litres, cost right at 5$ all in. I looked at the specs a while back and found its cold flow properties were better than Citgo, Motomaster (Citgo flavor) and T5 10w30. At the time, it cost less than all those. Not sure of the price point now but seeing as Alberta has half the tax, you could get a decent deal. I live about 3.5 hours east of you and PC bulk dealers litter the landscape.

I use it year round in my ISB6.7. I plug in on the real cold starts (sometimes not quite long enough) and never ran into any issues yet. Truck starts as well as any modern diesel with good batteries in the bloody prairie cold. This upcoming week it is due for another oil change and have the kit for another used oil analysis.

As previously stated, 10w30 has cold flow properties near that of a 5w40, but less expensive and usually more resistant to shearing. In a 24,000km change index, 2.87% fuel, the PC 10w30 went from the stated 12cSt (typical property) to 11.47. It had plenty of additives left as well.

Just an FYI for what our Canadian companies have to offer.