In current name brand oils is there any reason not to always use 5 W30 instead of 10 W30?

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In general, if the W # meets your cold temp requirements:
Narrow spread = Less plastic
Which is good.

However, 0W oils have a better base oil ... and you have to be careful what you are buying when buying 10W. For example I like M1 EP 10W-30 but prefer a 0W over inferior 10W-30s like dino or syn-blend.

With 10W, they can dump a dino or blend on you but with 0W you get a better oil without much needed research. Meaning when you buy a 0W, they can't dump a cheap dino or blend on you.
I'd rather a Synblend like Valvoline Maxlife 10w-40 with a KV100 >15 and an HTHS of 4 when temperature permits vs Mobil 1 0w-40 at KV100 12.9 & 3.5 HTHS but that's just me. Thicker base oil viscosity is better for your timing chain and cams anyways.
 
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With modern oils is there any reason not to always use the lowest cold rating with the same operating temperature rating oil? I have read that in the past 5 W30 oil had more additive and was less shear stable than 10 W30 but does that still apply today? Also even if my manual doesn't mention it, because it wasn't invented in 1992, is they any reason not to use 0 w30 oil in a car that calls for 5 or 10 W30 oil. It is my understanding that the first number is the viscosity when cold. Why not use the lowest cold rating while keeping the "hot" rating?
My answer Yes, and a decent oil, following my stroke i could not change my own but Valvoline Instant Oil Change is great and coupons are available. My girlfriend has a Chevy Cruz with 275K miles, Valvoline keeps it going.
 
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I try to use 10W-30 whenever possible. In general I like oils with low vm (vii) & low Noack.

I have used M1 EP 10W30 and some GTX Magnatec Full Syn 10W-30 and in the past Chevron Supreme 10W-30 (dino) but now I only use M1 EP when it comes to 10W.

Recently I bought some 5W-30 Kirkland for the price.
Never bought any xW-20 despite the fact that 2 of our cars specify 0W-20 and 5W-20 ... Too thin for me (maybe not for the engine! lol) But for example if I was forced to choose between 10W-30 dino or TGMO 0W-20 for my Tundra, I would take the 0W-20 which is also the recommended viscosity grade.

TGMO 0W-20 is supposed to be (or used to be) very good with lots of moly but I think that has changed.

The only 0W that I've ever bought was last year for a summer trip with a loaded car and I bought some M1 FS Euro 0W-40 and Casterol A3/B4 0W-40. I basically wanted a good 40 oil since the 0 is not relevant in the summer and was easy to find those in store.

Some experts claim that high(er) amounts of vm (vii) are not that bad and won't shear ... but I still try to avoid it.
In my view these oils compensated with high wear additives but loaded with plastics. Can that mean the base oil is the cheap factor? There is always a balance of additives but there is also a balance of price. The high Noack may suggest a weakness in base oil quality.
 

OVERKILL

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Unless you live in a northern Winter here is no reason TO use a 5w-30 over 10w-30.
All other things being equal a 10w-30 will be n=more oxidation resistant, less varnishing and run longer than a 5w-30.
Having said all the those differences are a bit academic as modern oils are so good 5w-30 especially synthetic ones are often quite stable.

But unless you are worried about pumping oil in the negative degree range no reason to go to 5w-30 except fuel economy in the minutes during warm up.
The EPA cycle is heavily biased towards this, which is the sole reason we see the trend to thinner oils.

That's not necessarily true, it depends on how the product is formulated. A PAO-based 5w-30 will typically have less VII than a Group III or III/II+ blend and since 10w-30 is obsolete and not required to carry modern specs, the odds of it being formulated with cheaper bases is quite high.

A couple of examples just using 5w-30's:
9.1 and 8.0% VII respectively, for Group III:
Screen Shot 2019-02-03 at 5.35.15 PM.jpg


VS, one blended with PAO and using only 2.8% VII:
Screen Shot 2018-05-07 at 6.07.34 PM.jpg


Now of course, all commercial oils are going to blended to price points, but the bar is higher for 5w-30's because they have to meet certain OEM approvals like Dexos, the Ford WSS specs...etc. While you'll typically only see SN or SN Plus on the 10w-30.
 
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That's not necessarily true, it depends on how the product is formulated. A PAO-based 5w-30 will typically have less VII than a Group III or III/II+ blend and since 10w-30 is obsolete and not required to carry modern specs, the odds of it being formulated with cheaper bases is quite high.

A couple of examples just using 5w-30's:
9.1 and 8.0% VII respectively, for Group III:
View attachment 85774

VS, one blended with PAO and using only 2.8% VII:
View attachment 85785

Now of course, all commercial oils are going to blended to price points, but the bar is higher for 5w-30's because they have to meet certain OEM approvals like Dexos, the Ford WSS specs...etc. While you'll typically only see SN or SN Plus on the 10w-30.

Not trying to be argumentative and am always willing to accept constructive criticisms but:
Keep in mind I wrote "all other things being equal"
So that obviosuly presupposes same lube stock, etc.

Then you write "what if the base stock is different, then you're wrong?"
Yes its absolutely possible to have a even 0w-30 that is high end, and is more stable than a 10w-30 that is made to lesser specs..
but I literally put this blurb in there to address this exact point in order to compare apples to apples which is what the OP was asking.
 
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The op lives in Michigan. I here it gets pretty cold, up there.
This is true.
But one must read what the OP actually asked
And that is the question we must answer.

Did he ask " I live in Michigan its winter should I use 0w-30, or 5w-30 or 10w-30?"
No. (the answer would be obvious)
He asked
"Is there a reason to not choose a 0w-30 over a 5w-30 or 10w-30?"
This is the exact question he asked and this is the exact question I answered.

For forums to work properly we must answer the question asked, not the question we want to have been asked.
 

SR5

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To me 10W30 is not obsolete as a grade, sure there are some OEM specs that limit the viscosity grade, like Porsche A40 or Dexos1, which don't allow 10W30. But you could say the same thing about HTHS or SAPS level.

However I can easily get a 10W30 that carries ILSAC GF-6A & API SP, and others that carry Euro A5/B5, and HDEOs that are API CK-4 & ACEA E9.

Cold starting & warranty aside (which is fair enough, but no relevant to me), I don't feel limited by the above selection.

I would also argue, that the reason manufacturers like GM / MB / Porsche / etc limit their approval to 0W-X or 5W-Y oils, is that they don't trust all their customers to understand winter (W) ratings, and their concern is a customer grabbing a hot climate oil in a cold climate and causing engine damage. By saying, use a MB approved 0W40 oil, it will work for everyone from Australia to Alaska.
 
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To me 10W30 is not obsolete as a grade, sure there are some OEM specs that limit the viscosity grade, like Porsche A40 or Dexos1, which don't allow 10W30. But you could say the same thing about HTHS or SAPS level.

However I can easily get a 10W30 that carries ILSAC GF-6A & API SP, and others that carry Euro A5/B5, and HDEOs that are API CK-4 & ACEA E9.

Cold starting & warranty aside (which is fair enough, but no relevant to me), I don't feel limited by the above selection.
Bit thin for you outback folks though isn't it? Land of the 40w-70.
 

OVERKILL

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Not trying to be argumentative and am always willing to accept constructive criticisms but:
Keep in mind I wrote "all other things being equal"
So that obviosuly presupposes same lube stock, etc.

Then you write "what if the base stock is different, then you're wrong?"
Yes its absolutely possible to have a even 0w-30 that is high end, and is more stable than a 10w-30 that is made to lesser specs..
but I literally put this blurb in there to address this exact point in order to compare apples to apples which is what the OP was asking.
Let's back this up a bit here, because it's your wording of the first bit that caused me to address your post and provide the examples I posted.

You stated:
palmerwmd said:
Unless you live in a northern Winter here is no reason TO use a 5w-30 over 10w-30.

Pretty straight forward. This stands on its own as a statement made, without qualifiers, that a 5w-30 will always have more VII; will always be inferior to a 10w-30. You've left no room for leeway in this statement. Are we in agreement on that in terms of how it is worded?

On to the second point.

You then follow it with the qualifier:
palmerwmd said:
All other things being equal a 10w-30 will be n=more oxidation resistant, less varnishing and run longer than a 5w-30.

This in no way reels back the absolutism of the first statement or implies that the reader should assume that there may be myriad exceptions to the first statement because you didn't state that:

All things are almost never equal.

Which is why I responded. Fair?

As you are aware, oils are formulated to a performance and price point, two things that are interdependent. If your performance point isn't that high because the grade doesn't have to pass stringent approvals, it's going to be a cheaper blended product.

The Mobil blending guide excerpt I posted shows some examples of "ideal" formulations where you can clearly see that the 0w-30 has more VII content than the 0w-20, which certainly supports the "all things being equal" premise, which I I have no issue with. But in application, those oils aren't going to be blended that way.

I didn't read what the OP asked as saying "if all oils were blended identically in terms of basestocks, why wouldn't I just use a 0w-30 or 5w-30", but rather, was asking about the spectrum of modern oils, which brings us back to my answer, and that is simply that it depends.

We have oils of the same grade that vary WILDLY in formulation (TGMO vs M1 EP 0w-20 for example), base selection and VII content, so I tend to object to making broad generalizations based on parameters that will never be constrained in the idealized manner presented in real life.

If we look at two Mobil 1 products from the same family, say Mobil 1 High Mileage in both 5w-30 and 10w-30:
Screen Shot 2022-01-25 at 10.00.52 PM.jpg

Screen Shot 2022-01-25 at 10.02.01 PM.jpg


With the limited information we get on an SDS, we can still see that while both have PAO in them, the 5w-30 has more. Now, we start going across brands and we'll find zero PAO in either of those grades with many of the brands, while if we go to a lube like Ravenol, all of a sudden it's majority PAO.

Does that help?
 
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even thinner real synthetics like Redline have a bit higher noacks. redlines 0-20 + 0-30 noack 9 the 5-20 a bit better @ 8 + their 5-30 is 6 as is my choice the 10-30 while it prolly uses NO VII as real synthetic 30's meet the 10-30 specs!!
 
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Let's back this up a bit here, because it's your wording of the first bit that caused me to address your post and provide the examples I posted.

You stated:


Pretty straight forward. This stands on its own as a statement made, without qualifiers, that a 5w-30 will always have more VII; will always be inferior to a 10w-30. You've left no room for leeway in this statement. Are we in agreement on that in terms of how it is worded?

On to the second point.

You then follow it with the qualifier:


This in no way reels back the absolutism of the first statement or implies that the reader should assume that there may be myriad exceptions to the first statement because you didn't state that:

All things are almost never equal.

Which is why I responded. Fair?

As you are aware, oils are formulated to a performance and price point, two things that are interdependent. If your performance point isn't that high because the grade doesn't have to pass stringent approvals, it's going to be a cheaper blended product.

The Mobil blending guide excerpt I posted shows some examples of "ideal" formulations where you can clearly see that the 0w-30 has more VII content than the 0w-20, which certainly supports the "all things being equal" premise, which I I have no issue with. But in application, those oils aren't going to be blended that way.

I didn't read what the OP asked as saying "if all oils were blended identically in terms of basestocks, why wouldn't I just use a 0w-30 or 5w-30", but rather, was asking about the spectrum of modern oils, which brings us back to my answer, and that is simply that it depends.

We have oils of the same grade that vary WILDLY in formulation (TGMO vs M1 EP 0w-20 for example), base selection and VII content, so I tend to object to making broad generalizations based on parameters that will never be constrained in the idealized manner presented in real life.

If we look at two Mobil 1 products from the same family, say Mobil 1 High Mileage in both 5w-30 and 10w-30:
View attachment 86124
View attachment 86125

With the limited information we get on an SDS, we can still see that while both have PAO in them, the 5w-30 has more. Now, we start going across brands and we'll find zero PAO in either of those grades with many of the brands, while if we go to a lube like Ravenol, all of a sudden it's majority PAO.

Does that help?
I dindt mean for my reply to come out as snarky as it did.

I interpreted the OPs question in one way and thought I had addressed the unequal base stock concern with my disclaimer.
But reasonable people can disagree on this in a nuanced way and you make a good argument.

Cheers :)
 

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even thinner real synthetics like Redline have a bit higher noacks. redlines 0-20 + 0-30 noack 9 the 5-20 a bit better @ 8 + their 5-30 is 6 as is my choice the 10-30 while it prolly uses NO VII as real synthetic 30's meet the 10-30 specs!!
10w-30 is not the only grade that can be blended as both a monograde and multigrade with a good Winter rating. PAO can allow one to do 0w-20 and 5w-20 in that manner as well, but blenders choose to use VII's to meet their performance targets for the product because VII content really isn't very high up the list of criteria, as @High Performance Lubricants can attest, it's more an artifact of the formulation and the blender's design goals for that product.

As an aside, your constant plugging of Redline over your tenure here gets tiresome, as is the incessant parroting that they are "real synthetics". It brings nothing of value to the discourse and makes you sound like a shill.
 
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With modern oils is there any reason not to always use the lowest cold rating with the same operating temperature rating oil? I have read that in the past 5 W30 oil had more additive and was less shear stable than 10 W30 but does that still apply today? Also even if my manual doesn't mention it, because it wasn't invented in 1992, is they any reason not to use 0 w30 oil in a car that calls for 5 or 10 W30 oil. It is my understanding that the first number is the viscosity when cold. Why not use the lowest cold rating while keeping the "hot" rating?

My 2 cents on this: 10w30 would be fine in your climate. I live with my parents in WI. My father has a 2000 Chevy Blazer with the 4.3L V6 Vortec engine. It has 279K on it right now and has been running Mobil 1 FSHM 10w30 for probably the last 5 years at the very least, through the winter and polar vortex, getting driven at least 250 miles per week as he drives to work and back. It still runs strong, with no unusual or bad noises of any kind that may indicate cam, lifter, or cylinder wear of any kind. 1-2 oil changes per year.
 
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My 2 cents on this: 10w30 would be fine in your climate. I live with my parents in WI. My father has a 2000 Chevy Blazer with the 4.3L V6 Vortec engine. It has 279K on it right now and has been running Mobil 1 FSHM 10w30 for probably the last 5 years at the very least, through the winter and polar vortex, getting driven at least 250 miles per week as he drives to work and back. It still runs strong, with no unusual or bad noises of any kind that may indicate cam, lifter, or cylinder wear of any kind. 1-2 oil changes per year.
That's what it's all about.
 
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Its doesnt matter 5 or 10 but I would use what your manual calls for unless you live in a state with cold winters and starting temperatures under 15F
 
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