Delo or Rotella

[wagoneer]

I hate slogging this age old debate, just curious enough to ask. Having heard most modern oil brands will do the job.

 

[highdesertranger]

I run Delo but I have run Rotella. it's just my parts guy stocks Delo. I don't think there is a big difference. highdesertranger

 

[29chico]

Neither.  I use Mobil Delvac in my 1985 f250 6.9l diesel and 1996 F150 with the 300 six.

 

[speedhighway46]

As long as an oil has qualified for the service rating recommended by the engine manufacturer, all the advertising hype and marketing claims are just a lot of snake oil to make one product be perceived better than the other, when in fact they are the same.

The API certification makes them all the same.

Don't waste your time getting sucked up in the "which oil companies is better" argument. Use the oil you want to use as long as it conforms to the specifications set by the manufacturer.

Just my opinion, of course . . .

 

[DannyB1954]

Whichever one is on sale.

 

[SternWake]

15w-40's ??

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2354338

http://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1633073

I am definitely not in the motor oil is motor oil camp, though I think finding any measurable differences in wear and performance would be highly unlikely between two such highly respected HDEO's ( Heavy Duty Engine oils)

However one oil could certainly hold up longer than another in the same usage, depending on basestocks, Viscosity index improvers, viscosity modifiers and resistance to fuel dilution.

In the above( dated) links the TBN number on the Delo is 9.0, the Rotella 10.8. Total Base Number is basically the acid fighting ingredients in an oil, and this number falls as the oil ages, and when it is around 2 it is said the oil is done for, having lost its ability to neutralize acids which form from byproducts of combustion and moisture from condensation. These do not always fall linearly, some oils will drop quick to 6 or 7 and level off declining slower, others decline at a different rate, so the Initial higher TBN relating to TBN retainment, is not really something to put money on.

ZDDP is an antioxidant and extreme pressure/antiwear agent. This also gets depleted as the oil ages, and the Rotella has more.

Delo Zinc:....1077 Phosphorus:....893
Rotella Zinc..1360 Phosphorus....1106

Calcium and magnesium are the 2 basic detergents/dispersants and their levels relate to how well an oil can clean the internal engine surfaces and keep them in suspension in the oil rather than redepositing elsewhere. Some motor oils go with one or the other but both of these use both.
Delo - 1121 PPM calcium....... 320 ppm Magnesium
Rotella 752 PPM calcium.......1083 PPM Magnesium

Molybdenum and Boron are antifriction additives

Delo .......69 PPM Moly......371 PPM Boron
Rotella....42 PPm moly.....10 PPM Boron

CST Viscosity at 100C

Delo: ....15.70
Rotella:...14.4

Both are 15w-40s bit at 100C the Delo is thicker.



HTHS viscosity is the High temp, High shear rating on an oil. it most accurately represents hot oil thickness in the loaded bearings. These specs are not always listed but some oils within the same Xw-XX group can vary very widely in their HTHS viscosities.

How well an oil resists shearing to a lighter oil is another factor differentiating Motor oils as well.

So the API starburst means the oil is acceptable in any application calling for such and such a weight of oil. there are other certifications from different manufacturers, some much more stringent than others and some oils will meet these, and others will not, even with the API starburst.

Organic elements do not show up on a Virgin or Used oil analysis. There could be some mitigating secret sauce in this department making one oil perhaps more suitable than another in a certain engine/ temperature Environment/ oil change interval.

If cold temperature starting is a factor, even two oils in the same 15w-40 'could' have different flow points, as well.

There are lots of motor oil myths out there. One of my favorite is that someone who uses 10w-30 in summer and 5w-30 in winter, when the HTHS viscosity of the 5w-30 might be higher than the 10w-30, making the 5w-30 theoretically be able to protect better in the event of say an engine overheating.

Mobil 1 5w-30 and 10w-30 is one such example, witht eh 'thinner' 5w-30 actually being thicker at 150C than the 'thicker' 10w-30

So motor oil might be so similar one could never ever realize any difference between brands, but one motor oil could simply hold up much better in a certain usage, and be able to go more miles before being worn out, and perhaps protect better if the engine overheats, or resist shearing to a lighter weigh oil better than another.

So In my Head, motor oil is most certainly not motor oil and all the same.

Not sure which of these two oils I'd choose. Likely the one sold in a 5 quart jug at wally world for the better price but if both were the same price, I'd go Rotella, probably.

DO note the linked VOA's are quite old, the formulations could have changed since these were published. Most automotive forums have favorite oils for their specific engines. Some oils are said to run quieter in certain engines than other oils.

 

[masterplumber]

I ran Rotela in my old Ford and it seemed to do well. But I run Delo in my Cummins. Reason for the change - smell. Really not joking, I think Delo smells decent for oil anyway, and Rotela stinks to me. But I do think as long as it's quality oil it's more important as to which filter your use.