Amsoil 0w-40 vs 5w-40

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Been running the signature series 5w-40 in my dads 2015 ecodiesel and my 2016 Cummins and love it. About to order more and I see they have a 0w-40 now. Just curious if anyone is running the 0w-40 and how they like it, as it does meet the specs for the two engines. I like the thought of the 0w for when snowmobiling and the trucks sitting in -15 for a few days with no place to plug in. I heard though with such a large gap between the weights, that the 40w is actually a little less, any truth to this?
 
Well since 5w40 meets the industry standard in terms of Cold Crank to - 30c / -22F, what is it you are hoping that 0w40 will do? I run a 10w30 in my diesels and it does fine even at the sub zero range.
 
The 0W, 5W, and 10W designations are based on cranking and pumping requirements at sub 0 temperatures. With the gap between 0W-xx and 5w-xx, there is a difference in the NOACK Volatility and maybe HTHS. In climates where it doesn't freeze it may be better to use the 5W-xx. I live in South Texas and it doesn't get freezing temps here. My car calls for 0W-20 but use 5W-20. It's cheaper and the NOACK is lower and the HTHS is the same. I could get away with running 5W-30 here.
 
Lol sorry guys. I read somewhere they said the bigger gap in the weight, so 0w-40 is a larger difference between cold and hot then say 10w-30. They say that big difference can effect the hot temp viscosity, so instead of it being 40, it could actually be 30. Doesn't make sense, just asking though. And I did call amsoil, not much help. I know the 5w-40 does fine in the negatives, but if I can have even better flow on those starts, that's always better
 
I'd stick with the 5W40 don't forget that diesel fuel is also a lubricant. of sorts)
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you will get NO answers from Scamsoil! they are well formulated to meet a spec using the cheapest synthetic they can, usually mostly group III's, they USED to be PAO + Ester + advertised as such, today not so much. on the wider spreads depends on the base oils used, a PAO 30W meets the 10-30 spec without a lot of undesirable viscosity improvers where as a mineral oil needs a lot + group III fake synthetics are somewhere between. viscosity improvers also vary some longer lasting than others, so to answer your question wider spreads with conventional oils are worse, synthetics not so much. theres little difference between 0W + 5W in the cold + lighter oils burn off more noted in the noack #'s of them. check + compare cold cranking #'s to see how they perform when cold, but these are new oils which can deteriorate + thicken over time, if its working why fix it!!
 
you will get NO answers from Scamsoil! they are well formulated to meet a spec using the cheapest synthetic they can, usually mostly group III's, they USED to be PAO + Ester + advertised as such, today not so much. on the wider spreads depends on the base oils used, a PAO 30W meets the 10-30 spec without a lot of undesirable viscosity improvers where as a mineral oil needs a lot + group III fake synthetics are somewhere between. viscosity improvers also vary some longer lasting than others, so to answer your question wider spreads with conventional oils are worse, synthetics not so much. theres little difference between 0W + 5W in the cold + lighter oils burn off more noted in the noack #'s of them. check + compare cold cranking #'s to see how they perform when cold, but these are new oils which can deteriorate + thicken over time, if its working why fix it!!
 
Compare the HTHS viscosities. For these two oils, they are closer than usual in viscometrics for 0W-40 and 5W-40 oils from the same oil lineup. HTHS for 0W-40 is 4.2 cP and it's 4.3 CP for 5W-40. The 5W-40 will probably lose a little more viscosity than the 0W-40 but not by much. It's been found that if the low-shear rate viscosity at 100 C decreases by x% due to permanent shearing of the polymer VIIs, the HTHS viscosity is likely to drop by roughly only 0.5x%. The viscosity losses due to fuel dilution cause more of an equal percentage decrease in both viscometrics. I think either oil would be a good choice in New York due to their similarity and non-extreme climate.
 
Benjy, you can't even spell "oops" properly. Stop with the Amsoil rants every chance you get! Like I've told you more than once before, there is PAO in their products, especially the SS line. Don't think that movie you're loading is slow, it's you that's slow.
 
JAG, after reading your comment, I went to amsoil's page and looked up the differences. I googled everything, but maybe you guys can explain better. How does the descriptions (kinematic viscosity and such) correlate with the numbers.

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Originally Posted by Buddyp
Lol sorry guys. I read somewhere they said the bigger gap in the weight, so 0w-40 is a larger difference between cold and hot then say 10w-30. They say that big difference can effect the hot temp viscosity, so instead of it being 40, it could actually be 30. Doesn't make sense, just asking though. And I did call amsoil, not much help. I know the 5w-40 does fine in the negatives, but if I can have even better flow on those starts, that's always better

You're correct, that doesn't make sense.
 
FWIW, the 0w40 DZF cranked up as easily as my former 5w30 HDD fill, and built oil pressure much the same.

It's been -25c or so (without wind chill) these past couple days on the middle part of the ON-QC border.

Didn't use the Webasto, truck wasn't plugged in, just a couple hits of the grid heater & started the old girl up.

I did have to smack her into 4x4 all the way to the major hwy.
 
Originally Posted by benjy
you will get NO answers from Scamsoil! they are well formulated to meet a spec using the cheapest synthetic they can, usually mostly group III's, they USED to be PAO + Ester + advertised as such, today not so much. on the wider spreads depends on the base oils used, a PAO 30W meets the 10-30 spec without a lot of undesirable viscosity improvers where as a mineral oil needs a lot + group III fake synthetics are somewhere between. viscosity improvers also vary some longer lasting than others, so to answer your question wider spreads with conventional oils are worse, synthetics not so much. theres little difference between 0W + 5W in the cold + lighter oils burn off more noted in the noack #'s of them. check + compare cold cranking #'s to see how they perform when cold, but these are new oils which can deteriorate + thicken over time, if its working why fix it!!


I dearly love the "fake" synthetic discussions. Especially when there are distinct advantages that Group III's have over Group IV PAO's. And the real world differences in performance for most folks are minuscule. I actually prefer a blend of Group III and Group IV in the motor oils I use. This article explains it....

https://www.machinerylubrication.com/Read/533/base-oil-trends
 
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