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Which oil brand to use?

21K views 49 replies 28 participants last post by  Broncowilly 
#1 ·
Hello everyone, new to the forum and I was wanting to pick everyone's brain on which brand of oil to use. I bought my first diesel truck (2014 Laramie Longhorn) and since it's used I will be doing the oil changes. I live in the south so 15W40 is definitely going to be the grade as well as synthetic but I'm having a hard time making up my mind on which brand to buy. Been looking at the Shell tella, my buddy uses Mobile 1 and I've been also looking at Royal Purple or Amsoil. Which do people preffer? your knowledge and experience is greatly appreciated. thanks
 
#2 ·
Except for break-in, I used the Amsoil 15W40 Heavy Duty Diesel and Marine exclusively. I sold the truck a few months ago at 200k, and the engine would purr as well as it ever had. Matter of fact, I had Amsoil in everything and couldn't be more pleased with the truck. But I honestly don't think you could really go wrong with any of today's top oils.
 
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#4 ·
The marine spec doesn't meet the DPF requirements on the new trucks. I am running the premium 15/40 amsoil synthetic on the next oil change. Currently running valvoline premium blue extreme 5/40 synthetic.
 
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#3 ·
Use whichever one you like, they are all good.

Most full synthetics you will find will be 5w40, dino oil being 15w40, usually.

I have been using the Delo 400 "Syntho-Syn" from walmart, $11.69/Gal, supposed to be dino oil with synthetic properties. Don't know about that, but it works fine for me. I tow heavy a lot and do 15K interval oil changes, I'm at 166K miles and all is well.
 
#5 ·
Factory Rotella for me, always been a fan. Thought about switching to Amsoil but no good place to get it locally for me.
 
#10 ·
I use Mystic 15-40 synthetic blend in my '97 now. Over the years, I've used Rotella, Delo 400, and a couple of others in the old truck. It's happy with all of them. I change it about every 8,000 +or-, and it uses about a quart between changes, at 420,00 miles. In the '14, I stuck with the Rotella T6 because the dealer did the first few changes, and that's what it was shipped with. After that I went to the Semi-synthetic Rotella.
 
#13 ·
Here's my theory, will there be a big enough difference between Dino and synthetic to legitimately cover the cost difference, maybe , maybe not. If what it gives you is peace of mind then the difference is one that can't be measured. At operating temps both oils will do the same. The two places I see a slight advantage for synthetic is start up, cold weather starts primarily and turbos. Synthetic is a little more "oily" or "slippery" and will get into more places quicker during start up, and since it's a thinner weight oil, will do so easier on those cold cold days. Now, his is what I have heard and somewhat believe. Synthetic oil can handle higher temps better and therefore is less prone to coking up turbos. Someone inform me if I'm right or wrong please
 
#14 ·
Basically.

Synthetic oil has smaller molecules, which makes it flow better, and fill gaps better. And, yes, most withstand much higher temps without breaking down.

I would use full synthetic in my truck, but I put so many miles on my truck, change the oil so often, that the increased cost is something I just can't justify.

I use full synthetic on my hotrods, but they only get their oil changed a couple of times a year, since they see so few miles.
 
#16 ·
in my '07 I used valvoline "Cummins" 15w-40 and went through about a Quart every 7500 miles, then switched to mobile delvac 15w-40 and for some reason went through about half that...I'm not too sure why...but I've used it in my '16 also, finding it at Walmart or a lot of other places is also a plus.
 
#34 ·
This reminds me of a very nice used 1980 Caprice Classic wagon with a 350 cubic, this was in the late 80s early 90s,,when I used Texaco it would take a quart between changes, I started using valvoline,and sometimes Exxon and it didn't take oil between changes,,I tried again and it did it again so I couldn't run Texaco, go figure. I really miss that car,but Yea I have to say I am with you on this one,lol
 
#17 ·
I run Rotella 15/40 conventional. Next oil change im switching to rotella 5/40 syenthic though. I hope its ok to switch to syenthic after running conventional for the last few years. We will see. But as some have stated there all good as long as the meet cummins or chrysler standards.....
 
#19 ·
There shouldn't be any problems from switching from conventional to synthetic. The level may seem a bit low with the first change to synthetic because it will get into the engine spaces and components better but EGT's should remain the same.
 
#20 ·
I'm noticing a lot of people are stating Valvoline, Rotella and Deno and Mobile 1300....these are conventional oils right? If so...how long are you waiting between oil changes? Only reason I'm asking is the Owner's manual says to change at 15000 miles but I'm not going to do that. I was looking more to 10,000 so I can keep the maintenance in align with fuel filters, rear differential, transfer case and transmission fluid changes.
 
#22 ·
Probably a 50/50 in use of conventional to synthetic. The brands you have listed all make a synthetic and conventional. Some make a blend of both. If you are looking for longevity, go with the synthetic, it will stand up better. I use Rotella T6 fully synthetic and change the oil and all filters between 12k-14k depending on the driving I do. I've never had any issues and the filters are all clean when I pull them.
 
#21 · (Edited)
Drinking The Kool-Aid !!

Despite public opinion, I am one of those Amsoil for life drivers, and have been using it for years throughout the ENTIRE truck!
Say what you will about this "Mystery Oil" - but as a Preferred Member I obtain it at Wholesale, appreciate the extended intervals, and though already being Brainwashed once at Paris Island upon my Marine Corps Enlistment, I am sticking by this gear no doubt!

Next to adding my special "Sight Glass" Rear Diff cover made especially for Geno's Garage by Mag-Hytec, FWIW Amsoil is my next best thing! **I can now see that nice clean Severe Gear Diff Fluid w just a glance! :grin2:
 

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#26 ·
Good Question ^^^^^ i have heard mixed messages about this, some saying synthetic from factory, some say not. Some Valvoline, some say Rotella. Its all over the place.
 
#32 ·
Your dealer is full-ON nutso.................

Since the engines are manufactured in Columbus, Indiana THEN shipped to the plant in Saltillo.......there's no way in KRAPPPPP that any specific truck on the line can be assigned engines with synthetic or without......
 
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#37 ·
I used to use rotella but switched to delvac. Rotella just makes the truck smell awful for the first 1000 miles. No idea why. I still use rotella in my tractor and syn rotella in motorcycles/dirt bikes.
 
#40 ·
When I first purchased my truck the previous owner ran Delo 400. I ran the truck with that oil for a few weeks before dropping it & switching to Amsoil 15w40 heavy duty marine & diesel oil. After the switch, it was literally a night & day difference for me!!! The truck ran way smoother & way more quite than before. Just my personal experience, highly recommend Amsoil if you can afford it💵

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