19+ Oil Grade selection... not a brand war

[AH64ID]

There have been several threads lately about oil on the latest generation of 6.7's so I thought I would bring all the thoughts and comments to one section.

Since the majority of us on here started our love of the CTD with a 5.9 or early 6.7 the current recommendation of 10w-30 seems thin, very thin. While there is speculation about whether or not it was FCA's way to get a little more fuel economy out of the truck (like the super thin stuff in cars these days) we do know for sure that the lifters need a thinner oil at startup than the flat tappet motors of 89-18.

If we go back to the 89-18 engines there were some distinct reasons to run 15w-40 and the flat tappets were the main reason, but did other bearings, cam journal, etc benefit from the 15w-40's high temp viscosity or was it purely for the flat tappet? Anyone have any input on that?

I also know that Cummins permitted the 6BT and ISB to run a 10w-30 oil on flat tappet motors as long as the high temp/high sheer rating was at least 3.5. What was this HTHS rating needed for? Flat tappets or something else?

On my 05 I had aftermarket oil temp and pressure gauges. When I went from a 15w-40 with a 100°C viscosity of 15.0 to one with a 100°C viscosity of 15.6 there was a noticeable decrease in oil temp and increase in pressure when towing hard. Makes me think the 10w-30, with a 100°C viscosity of ~12, will run hotter and thinner… but they did change the oil pump for 19+.

So that begs the question, what is the best oil for engine longevity?

All the 10w-30’s I’ve looked at meet the HTHS minimum
for older engines at 3.5-3.6.

10w-30 is thinner hot and cold than synthetic 5w-40... and then there are a few synthetic 10w-30's and 5w-30's too.

Without going into a brand war here are some brand specific specs comparing the two authorized oils.

Rotella T5 semi synthetic 10w-30 is thinner at 40° than T6 full synthetic 5w-40, but the T6 has a lower pour point by 9°F.

Amsoil full synthetic 10w-30 is thinner at 40° than their full synthetic 5w-40, and the 5w-40 has a lower pour point but only by 1°F.

Some other things to consider are that 10w-30 generally is less likely to burn off when working the motor hard vs 5w-40, but the 5w-40 has a better HTHS rating.

Yes... I am probably thinking about it too much and 99% of these trucks will get the cheapest 10w-30 they can find and NEVER have any oil related issues or faults as long as its changed at the recommended interval. With that being said, any other thoughts or input into the oil viscosity discussion?

I am personally leaning (51% at this time) towards a full synthetic 10w-30 being the best year round oil, but lets see what other input is made.

 

[gsbrockman]

Tuning in as I may see a 2019+ truck in my future......

I’m not very good at processing all the variables in regards to oil selection. I can say, however, that 5W40 has done me well in my previous 2014 RAM 3500 and current 2018 RAM 4500.

Edited to add pics of my engine in the 2014 RAM 3500 at 324k miles......ran with 5W40 synthetic and 13.5k to 15.0k OCI’s.
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[Rob S]

I’m sticking with 5-40

 

[AH64ID]

I’m sticking with 5-40

What’s your reasoning behind that?

 

[Killer223]

Good evening and Merry Christmas,
While im not an oil expert, i do know from my racing days that a big name brand manufacturer would run thinner oils than the rest of the crowd. and rarely was it a synthetic even in today's race program they run a dino oil.
Whats your idea of engine longevity? I pose this question because my 04 has ran everything from 10/30-15/40 with it being well over 300K now, i don't see a thinner oil impacting much but ease of start up and better economy. yes i did get better overall average mpg's running the Valvoline 10/30 than i did the rotella T6 5/40 or the Valvoline 5/40.
in my experience the engine sounded the same. started the same. etc. just got a little better mpg's
now i only towed with that oil a few times and kinda light loads and short distanced relatively speaking. trailer was about 13K and maybe 2K miles the first trip and 2400 the second one. there were several lighter 2K loads for 3-400 miles rather often. i usually get whats on sale. and some time i stock up on it. tractor supply had their house brand 15/40 on sale for 42$ a 5, i run that in the 12v.

My tractor calls for 0/40, 5/30, 5/40, 10/30, 10/40 15/40 oils. the valvoine10/30 is so far the best i've used in it. a lot quieter then the 15/40 and it quieted down faster than the 5/40 did. i've just picked up some rotella 10/30 for the next change on that one next year. i go about 300 hours on the oil.

I've read an article on Bob it the oil guy about oil's and temps. something along the lines of even a 5w oil was to thick for proper protection even at a 70 degree day.
i wouldn't think you'd want a higher viscosity oil, isn't that just resistance of flow? the flat tappets needed the thicker or higher viscosity for the added cushion when the cam lobs make contact. higher impact resistance.
Heavy loads up long hills. how is that defined.? towing lots of weight across the country i rarely saw much in the way of load. i cruise along at 1750 rpms' and light load. not hard on oil. up the hills sure. but the hills are short 1-25 miles. not long enough IMO the be much concern.

i stopped doing oil report because they all told me one thing. The engine in my truck didn't really care what brand and weight of oil i ran in it. and that it liked to be changed before 15K miles. my ocd making be change it 7500-10K on average. i went 15K a few times with TBN dropping to 3. so i changed the interval to under 10K and it was changed.

i'd imagine what your oil analysis program, you could do an experiment with the two grades of oil. and report your finding.
in these applications im more the thought 10/30 is fine. it's not a boat motor, or water pump under heavy load all the time.

 

[Rob S]

Covers all temperatures
Won’t void warranty
Easy to find
I like full synthetic

 

[nukegm]

Covers all temperatures
Won’t void warranty
Easy to find
I like full synthetic

x2

strange to me they still make dino oil.

merry christmas !

 

[AH64ID]

I too prefer full synthetic, which can be found in 10w-30.

 

[gsbrockman]

I too prefer full synthetic, which can be found in 10w-30.

What manufacturers offer the 10W30 in a diesel rated synthetic?

 

[AH64ID]

What manufacturers offer the 10W30 in a diesel rated synthetic?

Mobil Delvac is offered as a synthetic in 10w-30, and Amsoil has 2 different 10w-30’s. I haven’t done too much research past that.

Most l0w-30’s seem to be synthetic blends.

 

[Turbo Terry]

5/40 Delvac synthetic I think is pretty good oil. My new truck probably has 10/30 from the factory but will have 5/40 something synthetic in it before next winter for sure

 

[Turbo Terry]

5/40;Amsoil would be a good choice as well

 

[Ozymandias]

i stopped doing oil report because they all told me one thing. The engine in my truck didn't really care what brand and weight of oil i ran in it. and that it liked to be changed before 15K miles.

Exactly that because it is basically an industrial engine that runs all around the planet in the worst environments and with very limited maintenance - and performs well even treated so badly.

 

[NIsaacs]

Mobil Delvac is offered as a synthetic in 10w-30, and Amsoil has 2 different 10w-30’s. I haven’t done too much research past that.

Most l0w-30’s seem to be synthetic blends.

I wonder why that is? Synthetic blends seem to be growing as is full synthetic extreme. "Schaeffer's says the synthetic blends hold the additive package longer than full synthetic."

Since I have always used 15w-40 conventional in all my older diesel vehicles, I see no reason to change. Since I am not oil smart, I just went with what was recommended for my '21. Valvoline Premium Blue 10w-30 synthetic blend. My '17 Ford Escape recommends MotorCraft 5w-30 synthetic blend, so I use it. I have noticed that conventional gasser oil is getting scarce, so my last change on my Ford puller, I went with 10w-40 synthetic blend.

I will be following this thread, I might learn something

 

[JR]

I stock both 10w30 and 15w40 in Mobil Delvac Extreme. 15w40 for the truck, 10w30 for the tractor, Land Cruiser, mower, and all small engines. 10w30 pour point is -42°C. I believe the 5w40 is -46 or -48°C but would have to double check.... I personally do not use 5w40 if I can help it due to its thinner base oil blends and heavy use of viscosity index improvers and polymeric thickeners to cover the wide spread. At least on paper, 10w30 and 15w40 are more stable oils.

This is just opinion, but I believe the fact that people use the 5w40 with zero problems just enforces how easy the ISB is on oil. Of course staying within the OEM services it is hard to go wrong with either. My VW calls for 5w40 and I do run it but would be hesitant to run past the recommended intervals based on the oil starting to shear out on my UOA's. TBN, soot loading, fuel dilution, wear metals, etc have always returned good results. Viscosity trends thinner by 10k miles. The TDI's are just harder on oil than the ISB.

I have caught flack for saying this before, but the cold weather recommendations in the Ram owners manual are very conservative. Show me a farmer that changes to synthetic in the winter..... At least not in This climate that sees some sub zero weather thru the winter. I've never heard of an oil related failure, ever. I know the big farms around here on a personal level and am related to two of them. 15w40 (and more recently, 10w30)is the only oil in existence...

Also keep in mind many HD engines have been running 10w30 as FF for years now...some over 10 years. The ISX family and the 60 series come to mind. The ISB was one of the last engines to do away with the flat tappet architecture.

 

[Diesel Gunner]

Manufacturer Specifications driven by regulation is the answer here. If the emission regs did not change so rapidly, getting stricter and stricter there would not be the constant changing of oil specifications. Each time the know-it-alls hand down a new regulation from their appointed (not elected) thrones the engine manufacturers come up with a new spec to help their engines meet them.

In the 50's very high viscosity oils were very common. Engines got at least torn down and had the sludge cleaned out of them with very few miles on them compared to today's engines because of the oil formulations that were in use then. Modern lubricants are far superior to what was available then. Thus, engines stay cleaner, last longer, and lubricant caused failure is almost unheard of. Since the specifications change so often now, there is little motivation for the oil companies to create finished products that are "far superior" to their competitors. Additives are very expensive. Formulation is very expensive not because of the additives and base oils, but because of the 10's of thousands of hours of dyno testing and millions of miles of road testing that have to be done to meet the specification.

Synthetic oil is dino oil. It is just more highly refined. I use a syn-blend 15W40 in my truck and full syn 5W20 in both of my cars. Get used to the low vis oils fellas. 0W16 is here and it won't be long before 0W5 will become the new standard for small gasoline engine hybrid cars. Remember when 50W was the norm back in the day? Well, some of the younger guys won't, but technology changes things and sometimes even for the better.

 

[lpennock]

A thinner oil will actually run cooler than a thicker oil. This is because it flows faster allowing a faster heat exchange away from the parts. As tolerances are tightened a thicker oil will have more resistance to flow which will actually reduce the amount of lubrication because of the reduced flow and in the extreme can actually starve down stream parts of oil. As long as the oil can provide enough film strength to keep parts from rubbing together the thinner oil will actually do a better job as it will run cooler for less break down and provide protection sooner on start-up. Oil protects from wear by providing a cushion to keep parts from touching so as long as the oil has enough film strength it really doesn't matter if it is thinner and as tolerances get tighter the thinner oil can flow into where it is needed better. As Diesel Gunner said, expect thinner oils to become more the norm.

 

[AH64ID]

While that makes sense @lpennock I noticed the opposite on my 05. The thicker oil ran cooler and maintained better pressure. Both were 15w-40 thou, just slight differences in the 100°C viscosity.


The other thing that I had happen on my 05 was premature tappet wear from 5w-30 oil that met Cummins spec. That was before I towed heavy too. Nothing failed, but when I did a cam swap at 57K miles there was more wear than there should have been, but still not crazy. The UOA’s also weren’t as good as with subsequent 15w-40. That’s all a mute point with the new hydraulic lifters thou.

 

[Cummins12V98]

EVERY engine from 99 Tahoe 350, 15HP Kawasaki DR Mower, 01 Cummins, Honda pressure washer and 350 in my Boat get 15-40 AMZ/OIL Diesel and Marine. My 15 Cummins gets 15-40 Signature Series AMZ/OIL. Both 350's have hydraulic lifters. All engines have a lot of miles or hours with no issues.

So what would happen if I bought a 19 up Cummins and ran the 15-40 Signature series aside from getting slightly less MPG?

 

[AH64ID]

So what would happen if I bought a 19 up Cummins and ran the 15-40 Signature series aside from getting slightly less MPG?

According to the TSB it can cause deposits in the lifters and cause them to get noisy and possibly fail.