Why would you ever want to run 10W-30 over 5W-30?

[JohnnyJohnson]

I've always wondered this and never have figured it out.

Assuming you keep your RPMs below 2,500 until the car warms up, what would the point in running 10W-30 over When 5W-30? If anything I would think you would want to run 5W-30 over the other to get oil to the valvetrain faster.

When up to operating temps when you would go wide open throttle, both oils are the same weight.

When the 10W-30 was on sale with a rebate. Its not going to hurt a thing if you live in a winter climate that stays above zero.

 

[ka9mnx]

Why not use 5w 30 above 0f?

My bad 0c...
Here's what my book says. Why can't I use 5w30 above 32f?

View attachment 255642

Because your Jeep engine is probably an antique 4.0L with an antique owners manual. Same as my antique 4.9L Ford engine with it's antique manual specifying 10w-30.

EDIT: Forgot to mention the Dodge 3.9L that spec's 10w-30.

 

[Snagglefoot]

Grandpa ran Yellow Bottle. You can still get it and it’s now SP. However, in those days it was thought the smaller range in viscosity was a good thing. Modern 0W40 motor oil in high performance applications have mostly done away with that notion. Enjoy the shot.

 

[facility1]

does not a certain amount of engine wear briefly occur at start up, even at outside air temp above freezing?, thinking the reasoning also for the 0 or 5 w in a oil comes into play, and the CCS and the MRV numbers play a factor in selecting a oil is what I would consider , not always viscosity which can vary slightly with in its range due to the base stock used , and of course interlocking with the VII in a balanced additive package. Plus, when comparing oils making sure to take this into consideration along with the current specifications to be used ,not specs of a vintage (PQIA) chart. engine oil has improved and better formulated in recent times, for the application at hand.

 

[Pablo]

Honda 1.5T and 2.0T

 

[Lawnman23]

Still exists, but was way more common decades ago. I used to run it in the summer in my old Ford 300-6's. There however is really no reason - just go 15W-40

View attachment 255616

I ran that exact Castrol in my 98 K1500 for a OCI which resolved my RMS issue. I specifically wanted a HM 40 weight, not a thing for the 15w-xx flavors.

No complaints about it, started fine in single digit winter weather here in MN.

 

[OVERKILL]

could be, but the 10w-30 I'm buying isn't grII, and the off the shelf 5w-40 isn't going to be 60% PAO. I did preface synthetic 10W-30 to specifically exclude this comment.

Same blending choice could be make with Group III though (and the other oil in that slide would likely pass as "synthetic"). "Synthetic" doesn't mean they are going to use a heavy base oil blend, hence that Royal Purple 10W-30 example (an actual finished product) with 9.8% Noack.

My point is simply that this is a more complex discussion than as often presented, because there are so many different ways to get to the same end point and the large manufacturers are primarily driven by economics, particularly on grades that don't have to pass stringent manufacturer performance testing.

 

[OVERKILL]

So 10w30....... all other things being equal will not exhibit "more durable" characteristics like noted before?

Can you compare yours to a like 5w30?


As I have shown endlessly, my ignorance to some of these values regarding oil specs, I am trying to learn the magic....but to me, a higher flash point and higher volatility number especially in significant percentages has to mean something.........something meaningful so to speak.

The problem is that is often the case (as @Rand already mentioned), all other things generally are't equal, and this is particularly relevant when we are talking about OTS products and OE approvals, which drive formulation decisions after cost is factored-in.

AMSOIL's blending decisions are going to be different from say Shell, Mobil or Valvoline. Look at @SR5's Liquid Moly examples, MUCH closer on Noack than your AMSOIL ones, because of a different approach to blending. Look at my Royal Purple 10W-30 example. Ravenol 0W-40 has lower Noack and a higher flashpoint (8.5%, 236C) than the AMSOIL 5W-30, despite an even wider spread, and this is driven by the performance requirements of the approvals it carries.

HPL makes a 5W-30 with no VII's whatsoever, just using clever blending decisions and no cost constraints.

In the case of your AMSOIL examples, you observations are absolutely valid, the 5W-30 has a lighter base oil blend than the 10W-30. My point is simply that this isn't always the case and the topic becomes more complex once you start looking at OTS products from commodity blenders (where blending cost is a bigger factor) and widen the scope to include different brands.

 

[Pablo]

AMSOIL's blending decisions are going to be different from say Shell, Mobil or Valvoline. Look at @SR5's Liquid Moly examples, MUCH closer on Noack than your AMSOIL ones, because of a different approach to blending. Look at my Royal Purple 10W-30 example. Ravenol 0W-40 has lower Noack and a higher flashpoint (8.5%, 236C) than the AMSOIL 5W-30, despite an even wider spread, and this is driven by the performance requirements of the approvals it carries

This is the Amsoil OE 5W-30, Amsoil ASL 5W-30 is Noack 6.7% for clarity sake, always best to note which oil we are speaking about.

 

[OVERKILL]

Amsoil ASL 5W-30 is Noack 6.7%.

Yeah, his examples are from OE, which is of course one of the lower cost Amsoil options. We could also compare between AMSOIL tiers which further illustrates my point, as we'll see a range of these values looking at the different "tiers" of products, and that's within the product portfolio of a blender who isn't going to be inclined to formulate based on lowest possible cost.

 

[Pablo]

Yeah, his examples are from OE, which is of course one of the lower cost Amsoil options. We could also compare between AMSOIL tiers which further illustrates my point, as we'll see a range of these values looking at the different "tiers" of products, and that's within the product portfolio of a blender who isn't going to be inclined to formulate based on lowest possible cost.

Yes. Thanks. I edited my post, the species of oil was lost to me because the level of quotage.

Your point remains. Here is another way to make the point stand out. Look at 3 tiers of Amsoil motor oil comparing Noack or 5W-30 to 10W-30. (there are other varieties as well but not a 5W-30 or 10W-30 in that variety)

9.4 v 5.2
8.5 v 4.5
6.7 v 4.1

 

[martinq]

Yes. Thanks. I edited my post, the species of oil was lost to me because the level of quotage.

Your point remains. Here is another way to make the point stand out. Look at 3 tiers of Amsoil motor oil comparing Noack or 5W-30 to 10W-30. (there are other varieties as well but not a 5W-30 or 10W-30 in that variety)

9.4 v 5.2
8.5 v 4.5
6.7 v 4.1

Just so I'm reading this right. Volitility drops moving from 5w to 10w. It also drops as you move up the tiers? This is what I would generally expect.

5w vs 10w
Tier 1
Tier 2
Tier 3

 

[burbguy82]

The problem is that is often the case (as @Rand already mentioned), all other things generally are't equal, and this is particularly relevant when we are talking about OTS products and OE approvals, which drive formulation decisions after cost is factored-in.

AMSOIL's blending decisions are going to be different from say Shell, Mobil or Valvoline. Look at @SR5's Liquid Moly examples, MUCH closer on Noack than your AMSOIL ones, because of a different approach to blending. Look at my Royal Purple 10W-30 example. Ravenol 0W-40 has lower Noack and a higher flashpoint (8.5%, 236C) than the AMSOIL 5W-30, despite an even wider spread, and this is driven by the performance requirements of the approvals it carries.

HPL makes a 5W-30 with no VII's whatsoever, just using clever blending decisions and no cost constraints.

In the case of your AMSOIL examples, you observations are absolutely valid, the 5W-30 has a lighter base oil blend than the 10W-30. My point is simply that this isn't always the case and the topic becomes more complex once you start looking at OTS products from commodity blenders (where blending cost is a bigger factor) and widen the scope to include different brands.

I understand what you are saying.

I have learned a lot being here on the forum, thanks to you and others.

One of which is something that should have been obvious, that the "approach" can be different, have completely different properties, and still, very closely, do the same job, just in a sometimes very different way.

It is kind of like long range shooting, with different calibers, barrel lengths, etc, all on the same range. 300 winmag, 30-06, 308, 300BLk, 762x39, all require different input to make a hole at 300, but in the end you still get a .30 hole. I have to revert back to something more simple to make the connection.

 

[Stopsign32v]

It is kind of like long range shooting, with different calibers, barrel lengths, etc, all on the same range. 300 winmag, 30-06, 308, 300BLk, 762x39, all require different input to make a hole at 300, but in the end you still get a .30 hole. I have to revert back to something more simple to make the connection.

Depends if you are talking about the hole in the front or back.

 

[Jetronic]

does not a certain amount of engine wear briefly occur at start up, even at outside air temp above freezing?, thinking the reasoning also for the 0 or 5 w in a oil comes into play, and the CCS and the MRV numbers play a factor in selecting a oil is what I would consider , not always viscosity which can vary slightly with in its range due to the base stock used , and of course interlocking with the VII in a balanced additive package. Plus, when comparing oils making sure to take this into consideration along with the current specifications to be used ,not specs of a vintage (PQIA) chart. engine oil has improved and better formulated in recent times, for the application at hand.

it's during the initial cranking, when there may not be much if any oil available to feed to the lubricated surfaces. Time since last run is definitely a factor here (and how hot it got during that time switched off).

the winter rating only comes into play when the start up temperatures are below the winter, rating, or for aged oil 10°F above the winter rating

 

[Stopsign32v]

the winter rating only comes into play when the start up temperatures are below the winter, rating, or for aged oil 10°F above the winter rating

What about on the far other spectrum of the field? 0W oil in 95 degrees summer days when the oil is cold?

 

[Patman]

What about on the far other spectrum of the field? 0W oil in 95 degrees summer days when the oil is cold?

Under conditions like that you can look at the viscosity at 40c (104F), which most oil makers will publish. As an example, Mobil 1 0w40 has a viscosity of 78.3 cst at 100c. Compare that to M1 5w30, which has a viscosity of 62.2 cst at 100c. So even though it has better cold cranking ability to allow it to be rated a 0w oil, it’s actually not a thin oil at all like a lot of people have assumed, under most conditions it’s thicker.

 

[Pablo]

It also drops as you move up the tiers?

5w vs 10w
Tier 1
Tier 2
Tier 3

Purposeful formulation within a brand was the point. But comparison to other oil formulations, specifications, viscosity ranges it gets a lot more murky.

 

[Jetronic]

What about on the far other spectrum of the field? 0W oil in 95 degrees summer days when the oil is cold?

then you would be close to the 100°F rating of the oil, still much more viscous than it's going to be at 212°F or above. the viscosity would be more related to it's hot viscosity rating than the winter rating but it's often true that oils with a wide viscosity spread like 0W-40 will be thinner than oils with a lower spread like 15W-40.

 

[Stopsign32v]

Under conditions like that you can look at the viscosity at 40c (104F), which most oil makers will publish. As an example, Mobil 1 0w40 has a viscosity of 78.3 cst at 100c. Compare that to M1 5w30, which has a viscosity of 62.2 cst at 100c. So even though it has better cold cranking ability to allow it to be rated a 0w oil, it’s actually not a thin oil at all like a lot of people have assumed, under most conditions it’s thicker.

So I guess my question would be

WHY would 0W-40 not be the best hot temperature oil?

WHY would 0W-40 not be more popular than the traditional 10W-30 for summer (which seems to be the default).