Dodge Cummins Diesel Forum banner

1 - 20 of 59 Posts

·
Registered
Joined
·
373 Posts
Discussion Starter #1
OK, being an old retiree and not much to do except read too much into things, I have tried to understand what would be the best viscosity Synthetic oil to use in my truck. I know what the owner’s manual says, and I live in FL. So, I have been using 15W-40 (T4, T5). The last couple oil changes I used, 5W40 (T6, and then Valvoline). I really liked the Valvoline Extreme the best as the engine ran so smooth with good mileage. Amazon has it for sale at $59.70 for case of 3. I see now that the Shell T6 comes in 15W-40 at $89.64 for case of 3. So, my recent oil change, I went with T6 15W-40. The reason I used it was that when I ordered the Valvoline 5W-40, it go returned to Amazon undeliverable for whatever reason, so I reordered the T6 to try. It seems to run good, but I still like the Valvoline better. Now, my question is, why does Shell have the 15W-40 and Valvoline doesn’t. I tried to read about all these Viscosity Index Improvers, to the point of my old brain exploding. The only thing I got out of all this is that it does seem to take a lot of Viscosity Improvers to get the oil from 5W to 40 when hot. I’m not sure that much improvers will actually hold up good enough to really keep the oil at 40 when hot for the duration of the oil change. Seems that the less Improvers needed, as in 15W-40, would be better in keeping the range required. Am I reading too much into this?:stirpot:
 

·
Registered
Joined
·
307 Posts
Don't forget about Walmart delivery...I got Shell T6, 15w40 to the door for ~$60. Much better price than Amazon.
 

·
Registered
Joined
·
3,000 Posts
Any of those oils and grades will work fine for you. I get T6 Rotella on sale because with mail in rebates that they usually offer it ends up being the cheapest synthetic I can get. I get synthetic as I need 5w40 for cold weather.
 

·
Go Packers
Joined
·
5,374 Posts
We have a few stores that put Valvoline Premium Blue 15/40 on sale now & then for $10.99-$11.99 a gallon. I usually get 9 gallons when on sale. Then hopefully it's on sale again when I get down to the last 3 gallons.
 

·
Registered
Joined
·
373 Posts
Discussion Starter #7
Yes, you are reading too much into it. That's OK though as we all do that from time to time. If you like the Valvoline then run it and find something new to stress over, like grid heater bolts or turbo actuators. Those seem to be popular things to worry about these days.:grin2:
I worry about those too. You're right though, I'm surprised I lasted this long worrying about everything. :confused013:
 

·
Registered
Joined
·
6,003 Posts
OK, being an old retiree and not much to do except read too much into things, I have tried to understand what would be the best viscosity Synthetic oil to use in my truck. I know what the owner’s manual says, and I live in FL. So, I have been using 15W-40 (T4, T5). The last couple oil changes I used, 5W40 (T6, and then Valvoline). I really liked the Valvoline Extreme the best as the engine ran so smooth with good mileage. Amazon has it for sale at $59.70 for case of 3. I see now that the Shell T6 comes in 15W-40 at $89.64 for case of 3. So, my recent oil change, I went with T6 15W-40. The reason I used it was that when I ordered the Valvoline 5W-40, it go returned to Amazon undeliverable for whatever reason, so I reordered the T6 to try. It seems to run good, but I still like the Valvoline better. Now, my question is, why does Shell have the 15W-40 and Valvoline doesn’t. I tried to read about all these Viscosity Index Improvers, to the point of my old brain exploding. The only thing I got out of all this is that it does seem to take a lot of Viscosity Improvers to get the oil from 5W to 40 when hot. I’m not sure that much improvers will actually hold up good enough to really keep the oil at 40 when hot for the duration of the oil change. Seems that the less Improvers needed, as in 15W-40, would be better in keeping the range required. Am I reading too much into this?:stirpot:
You are too worried, like Wyo said, there are other things on these trucks to worry about.............NOT. I'll bet you this, if I change your oil, and you drive it, you can not tell me what oil I installed. Any oil that is correct for the engine will "feel" the same.
 

·
Registered
Joined
·
1,753 Posts
OK, being an old retiree and not much to do except read too much into things, I have tried to understand what would be the best viscosity Synthetic oil to use in my truck. I know what the owner’s manual says, and I live in FL. So, I have been using 15W-40 (T4, T5). The last couple oil changes I used, 5W40 (T6, and then Valvoline). I really liked the Valvoline Extreme the best as the engine ran so smooth with good mileage. Amazon has it for sale at $59.70 for case of 3. I see now that the Shell T6 comes in 15W-40 at $89.64 for case of 3. So, my recent oil change, I went with T6 15W-40. The reason I used it was that when I ordered the Valvoline 5W-40, it go returned to Amazon undeliverable for whatever reason, so I reordered the T6 to try. It seems to run good, but I still like the Valvoline better. Now, my question is, why does Shell have the 15W-40 and Valvoline doesn’t. I tried to read about all these Viscosity Index Improvers, to the point of my old brain exploding. The only thing I got out of all this is that it does seem to take a lot of Viscosity Improvers to get the oil from 5W to 40 when hot. I’m not sure that much improvers will actually hold up good enough to really keep the oil at 40 when hot for the duration of the oil change. Seems that the less Improvers needed, as in 15W-40, would be better in keeping the range required. Am I reading too much into this?:stirpot:
Don't get too wrapped up in all that VII talk. If you really want to get into it, try Bob Is The Oil Guy. Those guys are serious. About what, I'm not sure

https://www.bobistheoilguy.com/forums/ubbthreads.php

5W-40 synthetic is virtually always superior to any 15W-40 non synthetic. Period. Doesn't mean the 15W-40 is bad, it's just that the synthetic is better.

Maybe a 15W-40 is more gooder if your engine is about to rattle itself to death and you just want to keep it alive for another few months... It's also cheaper, if that's important to you. To some people, it is. Those that change their oil every other month and don't do it themselves, the costs can add up.

But if you're doing it yourself and/or the only difference in cost is the extra $10-$20 for the oil once or twice a year, it's a no-brainer. 5W-40 Synthetic all the way.

Oh yeah, the Amazon guy dropped my oil in the back of his truck and splattered it all over the place. So mine had to be re-ordered, too.
 

·
Registered
Joined
·
790 Posts
Stick with 15w40 conventional. It will work absolutely fine in your climate. It's cheap as well.

Synthetic is great but conventional has come so far, base oil is a non issue.

I think it was valvoline that did some wear testing. The lower the spread between the W and viscosity at 100C the better wear protection. 15w40 does better than 5w40, which is better than 0w40.

Obviously cold climate dictates your W.

Viscosity is another story. 30 weights are fine, as are 40 weights. Cummins even states this.

Run a 15w40, 5w40 or even a 10w30. If its CES20081/86 it's fine. No one will care, not even your engine.
 

·
Registered
Joined
·
280 Posts

·
Registered
Joined
·
194 Posts
You are too worried, like Wyo said, there are other things on these trucks to worry about.............NOT. I'll bet you this, if I change your oil, and you drive it, you can not tell me what oil I installed. Any oil that is correct for the engine will "feel" the same.
To the OP-Your truck does not know what oil you put in it. It doesn't run smoother with one oil or another and I can assure you the mpg is the same.
It's all in your head. Just buy whatever is cheapest and locally available of the correct viscosity. No need to spend the extra $$ on synthetic oil. Change your oil and filter at the specified intervals and you will have nothing to worry about.
:wink2:
 

·
Registered
Joined
·
229 Posts
I have been using Walmart SuperTech HD Diesel 15/40 <$10.00 a gallon with "0" issues. Oil is changed with filter at 6 months with 6 - 7K on the oil. I have sent off 3 samples to Blackstone labs over the past 5 years all with good reports. At less than $45.00 a change I see no reason to switch to a higher dollar motor oil.
 

·
Registered
Joined
·
2,848 Posts
Go buy 3 gallons each of each of the types of oil you're pining over.
Get a few new 5 gallon buckets with lids and have your wife pour each brand into a different bucket and number them 1, 2, 3, 4....
Tell the wife to write down which bucket has which brand of oil and to NOT tell you until you've run through all the buckets and have formed an opinion of each.

Then when she reveals your top choice, you'll know which one is best.
(Disclaimer, T4 will be a dead giveaway, because that stuff stinks, literally. They don't call it Rosmella for nothing, so if that's part of your test, you'll be able to cheat with that one...)

I treated my truck to an oil mix tail last week. Figured variety is the spice of life and I wasn't going to the store, so...
I had most of a gallon of T6 that I use in my bikes with wet clutches, a jug and a half of Valvoline Blue and an old gallon of Delo (it got lost on the back of the shelf).
The truck LOVES it! (Actually it doesn't care and neither do I...lol)
 

·
Registered
Joined
·
2,198 Posts
A Cummins can run on a mix of molasses & olive oil, if need be.

Heck, if vegetable oil came in 15w40 & had the correct CK-4 cert for your year, I'd use that in FL.
 

·
Registered
Joined
·
2,848 Posts
^This.
But I typically save the molasses for cookies and olive oil for sauteing veggies and making salad dressing. 15W40 is cheaper by the gallon!
 

·
Registered
Joined
·
451 Posts
Now, my question is, why does Shell have the 15W-40 and Valvoline doesn’t. I tried to read about all these Viscosity Index Improvers, to the point of my old brain exploding. The only thing I got out of all this is that it does seem to take a lot of Viscosity Improvers to get the oil from 5W to 40 when hot. I’m not sure that much improvers will actually hold up good enough to really keep the oil at 40 when hot for the duration of the oil change. Seems that the less Improvers needed, as in 15W-40, would be better in keeping the range required. Am I reading too much into this?:stirpot:
The synthetics might not even need viscosity modification to get the desired range.

I don't know the details of each but "synthetic" is a marketing term in the US and can mean either a very highly refined Group III base oil or Group IV base oils. A group III oil would probably require a lot of additional additives to get a 5w40 range while a Group IV oil probably wouldn't.

Shell could be just saving production costs by staying with a Group III and fewer additives....

Modern oil is so good it generally doesn't matter what you run as long as it has the right specs....
 

·
Registered
Joined
·
2,198 Posts
Very true on the Grp 3 with VIIs vs Grp 4.

As I do just one annual oil/filter change, I use a true Grp4/PAO in Amsoil 15w40 flavor with a Donaldson SynTeq; the old beater cranks up on unaided starts as easily as T6 5w40 down to approx -8f.

Though, usually, I hit the Webasto for a few at anything below 0f, to defrost the windshield & warm up the fuel; lets me wear thinner socks as well.

In addition, I'd rather use a semi syn Grp3 10w30 like Petro Canada Duron/Rotella T5 over a 5w40 like Rotella T6/Valvoline "Extreme".
 

·
Registered
Joined
·
73 Posts
I use shell rot T . my truck has 176000. i sample and am told the oil is OK at 60000 mils. that is when i change. ive done the with the last 3 trucks. all cumines i usely trade at 300000 mils. i usely run over 100000 mils per year
 
1 - 20 of 59 Posts
Top