Oil recommendation - Winter/Summer L5P

[jesco88]

Hey all,

I’ve been trying to stick one brand/product line of oil for my 2021 L5P. I typically run 15w-40 from April until end of Oct, then switch to a 5w-40. On average, I’m changing the 15w40 with about 7000-8000 miles on it, and only getting 5000-6000 miles (but similar run hours as summer) on the 5w40 during the colder months.

I’m not able to easily find the same brand/label/flavor of oil in 5w40 and 15w40. I have tried Rotella T6 in a 5w40 and 15w40 and I get the "tick" that many others have reported. I don't think its a big deal, but I don't believe I ever noticed the tick with the Delvac Extreme 15w40.

I've thought about running a 5w-40 year round, but it does get to triple digits here in the summer from time to time, and that's really when I'm getting to the mountains with the travel trailer. This truck doesn’t seem to care about elevation or grades, but I do work the truck much harder in the summer. Pair that with my own hesitancy of deviating from the owners manual that states to run 15w-40 unless the ambient temp is below 0F.

So I have a couple of options..

Rotella T6 in 5w and 15w is ~$60-70 per 2.5gallon jug. ($130 per year)
AMS Oil (non signature) in 5w or 15w is ~$70 for a 2.5gallon jug +$16/yr pc ($156 per year)
Delo 400 XSP 5w-40 is $99 for 3x1gallon jugs and then $50 for the 2.5G 15w40... ($150 year)
Mobile 1 doesn’t seem to offer one synthetic product line with 5w-40 and 15w-40. So I could run Delvac Extreme 15w-40 and TDT or ESP in 5w-40.

The more and more I look for one flavor of oil that is offered in both 5w-40 and 15w-40, the more I am just wanting to be lazy and order the AMS Oil online and have it shipped to my door and be done with it. Seems like it will work out to be the same price as Delo... I've never run AMS Oil and it seems like most choose it for longer OCI, not for the reasons I'd be choosing it.

Any suggestions?

 

[fantastic]

5w-40 all year for 12-13k miles. That would afford you an oil sample each year also instead of paying for x2 changes in a year. Amsoil has already been tested along with some others. Here's a few on this list you can check out. Based on the oxidation alone on the Amsoil appears to be not as robust as the Rotella T6 that has better base stock. I'm not aware of some VOA values on the Delvac but I know it's a solid oil. I do know that T6 has the same add pack in both viscosities.

VOA Diesel Oil Database

I stumbled across himemsys thread that combined a bunch of Gasoline VOA in one spreadsheet. I figured it was such a great idea that I decided to also put one together but with Diesel Oil instead. I made this version similar to that one in order to minimize confusion. I created a line that adds...

bobistheoilguy.com

 

[c502cid]

I run 75% 5w-40 and 25% 15w-40 year round in most everything I have that pulls or hauls. Why? Because I want to. lol

 

[userfriendly]

That tick is just valve train clatter. Enjoy.
Have a look at Delo 400 5w40, it’s the thickest. You can buy 5 gallon pails at any Chevron bulk fuel and lubricant outlet.
Get a commercial account and save on diesel fuel too.
www.oronite.com

 

[fantastic]

That tick is just valve train clatter. Enjoy.
Have a look at Delo 400 5w40, it’s the thickest. You can buy 5 gallon pails at any Chevron bulk fuel and lubricant outlet.
Get a commercial account and save on diesel fuel too.
www.oronite.com

If the PDF manual is anywhere near reality it would indeed be some of the thickest 5w-40 I've seen that you can grab off the shelf. Amsoil appears to be a spec thicker though.

 

[userfriendly]

I run 75% 5w-40 and 25% 15w-40 year round in most everything I have that pulls or hauls. Why? Because I want to. lol

I don’t have to do that because Petro Canada has 10W40 Duron.
But I did a 50/50 15W40 T5/0W40T6 last May in my daughter’s 2018 L5P.
Friends don’t let friends use Rotella.
I’ve switched at least 6 GMs 1500s and HDs to 80W140 from 75W90.

 

[CleverUserName]

RLI 5w40 has an HTHS of 4.8 cP. It’s the thickest HD oil I can think of.

 

[dnewton3]

Dmax engines generally don't care what brand/grade is used; the wear rates are not affected by these choices.
You don't need to overthink this.
Unless you expect to get below 0 degF fairly frequently, then just run a 15w-40 year round.

 

[jesco88]

Dmax engines generally don't care what brand/grade is used; the wear rates are not affected by these choices.
You don't need to overthink this.
Unless you expect to get below 0 degF fairly frequently, then just run a 15w-40 year round.

Hrmm, I don't think I'm overthinking anything here... I just paid off a 70k truck, and we're on a engine oil forum. Asking for advice on engine oil seems appropriate, not overthinking. I live in a fairly remote region in North East Idaho. It was -40F in January. I will not run 15w-40 year-round. My experience has been to run the brand of oil in the engine for a while, and not flip-flop between brands. Something about different additive packages etc, not an expert just going of experience.

 

[userfriendly]

Hrmm, I don't think I'm overthinking anything here... I just paid off a 70k truck, and we're on an engine oil forum. Asking for advice on engine oil seems appropriate, not overthinking. I live in a fairly remote region in North East Idaho. It was -40F in January. I will not run 15w-40 year-round. My experience has been to run the brand of oil in the engine for a while, and not flip-flop between brands. Something about different additive packages etc, not an expert just going of experience.

You’re right about not flipping between brands and additive packages. Caltex has an instructional video on that subject, and from personal experience, switching brands causes high copper in the UOAs from the oil cooler.
That’s one of the reasons I suggested Delo. They have several grades with the same additive package and can be mixed if necessary to use up bottoms.

 

[jesco88]

You’re right about not flipping between brands and additive packages. Caltex has an instructional video on that subject, and from personal experience, switching brands causes high copper in the UOAs from the oil cooler.
That’s one of the reasons I suggested Delo. They have several grades with the same additive package and can be mixed if necessary to use up bottoms.

Yep, I think I might switch to the Delo 400 XSP. For whatever reason though, I cannot find a 2.5G jug of the 5W-40 variant. Only 1 gallon, and its $32 a gallon. At that rate, its nearly the same price as the AMS Oil "heavy-duty" (non-signature series)... I doubt there's much difference between them, but from a consumer's POV, the AMS Oil is easier for me. I just order it online and it shows up at my door. And I can order their Oil Filter, which is supposed to be one of the better oil filters out there for this truck.

 

[fantastic]

Yep, I think I might switch to the Delo 400 XSP. For whatever reason though, I cannot find a 2.5G jug of the 5W-40 variant. Only 1 gallon, and its $32 a gallon. At that rate, its nearly the same price as the AMS Oil "heavy-duty" (non-signature series)... I doubt there's much difference between them, but from a consumer's POV, the AMS Oil is easier for me. I just order it online and it shows up at my door. And I can order their Oil Filter, which is supposed to be one of the better oil filters out there for this truck.

From what I've seen the Delvac Extreme 15w-40 is some great oil. I have a 5 gallon pail of it in the garage going into the sump come November. It suggests up to x2 Drain Interval. You can buy it with a $30 rebate in the spring rebate promotion around March or April. Paired with an analysis test it would be an excellent annual oil IMO.

Here's a recent result with 11k on it. It came back in excellent shape! Also shows a Virgin Oil Analysis too.

‘15 RAM 3500 Laramie Longhorn - 86k - Mobil Del Extreme - 11k

Looks good to me? 🤷🏻‍♂️ Maybe I’ll extend it to 15k. 86,780 on unit 11,080 on oil/8 months time 15w40 silver jugs This was with a Fram 20k filter and pulling a 40’ 5th wheel for 50% of the miles.

bobistheoilguy.com

 

[userfriendly]

Yep, I think I might switch to the Delo 400 XSP. For whatever reason though, I cannot find a 2.5G jug of the 5W-40 variant. Only 1 gallon, and its $32 a gallon. At that rate, its nearly the same price as the AMS Oil "heavy-duty" (non-signature series)... I doubt there's much difference between them, but from a consumer's POV, the AMS Oil is easier for me. I just order it online and it shows up at my door. And I can order their Oil Filter, which is supposed to be one of the better oil filters out there for this truck.

The best filter could be the blue one from GM. Gran-Del Petroleum Products in Boise might be your closest if you’re in the Kalispell area.

 

[CleverUserName]

Hrmm, I don't think I'm overthinking anything here... I just paid off a 70k truck, and we're on a engine oil forum. Asking for advice on engine oil seems appropriate, not overthinking. I live in a fairly remote region in North East Idaho. It was -40F in January. I will not run 15w-40 year-round. My experience has been to run the brand of oil in the engine for a while, and not flip-flop between brands. Something about different additive packages etc, not an expert just going of experience.

-40F is below the temperature range of a 5w40. You should be using a 0w40 year round if you want to stick with one oil.

 

[Bighorn2500]

I typically run either 5w40 Rotella T6 or 5w40 Valvoline Premium Blue Extreme year round in Michigan which can see highs in the upper 90’s breaking 100 occasionally and has seen -19F starts in the Upper Peninsula during snowmobile season not being able to use the engine block heater either. No issues running 5w40 year round.

 

[jesco88]

From what I've seen the Delvac Extreme 15w-40 is some great oil. I have a 5 gallon pail of it in the garage going into the sump come November. Isuggests up to x2 Drain Interval.

Yep, that’s the exact oil I switched to when I hit around 10k miles. Been running synthetic ever since. The question is what to run after I drain out the 15w Delvac come Oct/Nov to Feb/Mar when temps are well below 0F in the daytime. Maybe Mobil ESP in 5w40? Not sure how well those would pair.

 

[fantastic]

Yep, that’s the exact oil I switched to when I hit around 10k miles. Been running synthetic ever since. The question is what to run after I drain out the 15w Delvac come Oct/Nov to Feb/Mar when temps are well below 0F in the daytime. Maybe Mobil ESP in 5w40? Not sure how well those would pair.

The Rotella 5w-40 would be cheaper if you can't get a rebate on the Mobil. Plug in below 20 degrees with 15w.

 

[JBMoy]

On my third Duramax driven daily in north east Pennsylvania. After trying all kinds of brands and mixes over the years I’ve settled on Mobil 5w40 for all 10 qts between November and March. Summer oil changes get 2 gallons of Mobil delvac 15w40 and 2 qts of 5w40. This is just mainly due to the 5w40 being packaged in quart bottles. Winter starts are much better with a 5w40. Sub zero temps are not an issue. OCI is anywhere between 5000 and 7500 miles.

 

[MSCH]

Hey all,


I've thought about running a 5w-40 year round, but it does get to triple digits here in the summer from time to time, and that's really when I'm getting to the mountains with the travel trailer. This truck doesn’t seem to care about elevation or grades, but I do work the truck much harder in the summer. Pair that with my own hesitancy of deviating from the owners manual that states to run 15w-40 unless the ambient temp is below 0F.



Any suggestions?

5W40 year round is a good choice... no difference in hot weather abilities of either 15 40 or 5 40...
cold weather starting is better in a 5w40... which sounds like your main concern.
brand you use makes no difference, and switching brand makes no difference
so just pick the one you want to use by whatever criteria you care to apply.

 

[CleanSump]

40 is 40. Your engine doesn't get more protection from 15W vice 0/5W in the Summer.
Pick the 0/5W that is most convenient or gives you the warm fuzzies and worry about fuel gelling in the Winter instead.