Is 5W and 0W essentially the same flow/lubricity at 40-60F +?

[apollo18]

Hello correct me if I am wrong however this is the info that I learned over the years and not sure if I am correct or not

The first digit before the W is the winter rating
So 0w will flow better then 5w at super cold cold temperatures

However for this example lets use we are comparing a full synthetic 0w vs a full synthetic 5w

At a temperature of 50-60F, would they both flow the same? Or is 0w still better?

The reason I ask is because if someone lives in really warm temps all year round then what’s the purpose of even running a 0w? Unless I’m mistaken it would never really be put into a temperature that would show it’s benefit over soemtbing like a 5w

The reason I was thinking of sticking to a 5w etc rather then Just always doing 0w is technically isn’t it said that 5w will sheer less compared to a 0w since they have less VI improvers compared to a 0w?

Also it seems like the selection is more for a 5w30 compared to a 0w30



However if I am mistaken please correct me I would love to learn!!

 

[SC Maintenance]

Looking forward to the answers.

I have shied away from 0W fluids because thinking they had more vii - and the cold weather rating is irrelevant to where I live as well.

At the same time, I have used 10W-30 instead of 5W-30 - but in looking at the SDS of various oils - it seems the 10W-30 would seem to have less of the higher group level oils - so it seems its an older and maybe not as good formulation, so I tend to continue with 5w-30.

 

[kschachn]

Same-grade oil with a 5W winter rating is essentially the same above -30, not just 40-60 as you noted.

And flow is irrelevant here. It’s about cranking and pumpability and that’s not anywhere near a concern at 40-60F.

Shear stability is highly dependent on both the engine and the VII quality. Few engines have a documented problem with mechanical shearing of the VII. Buy a good quality name/brand oil and it’s highly unlikely you will have a problem with shear regardless of the grade.

And lastly many oils with a 0W winter rating use base stocks that have a naturally higher viscosity index and therefore utilize less VII. It’s not something I worry about.

 

[BMWTurboDzl]

Hello correct me if I am wrong however this is the info that I learned over the years and not sure if I am correct or not

The first digit before the W is the winter rating
So 0w will flow better then 5w at super cold cold temperatures

However for this example lets use we are comparing a full synthetic 0w vs a full synthetic 5w

At a temperature of 50-60F, would they both flow the same? Or is 0w still better?

The reason I ask is because if someone lives in really warm temps all year round then what’s the purpose of even running a 0w? Unless I’m mistaken it would never really be put into a temperature that would show it’s benefit over soemtbing like a 5w

The reason I was thinking of sticking to a 5w etc rather then Just always doing 0w is technically isn’t it said that 5w will sheer less compared to a 0w since they have less VI improvers compared to a 0w?

Also it seems like the selection is more for a 5w30 compared to a 0w30



However if I am mistaken please correct me I would love to learn!!

Putting the Simple Back into Viscosity - Bob is the Oil Guy

by John Sander, VP Technology, Lubrication Engineers Inc. Abstract: Simply stated, viscosity is defined as the internal resistance of a fluid to flow. That doesn’t sound too difficult, does it? Unfortunately, new temperature, speed and pressure demands on lubricating fluids have changed over the...

bobistheoilguy.com

 

[Titan]

And flow is irrelevant here. It’s about cranking and pumpability and that’s not anywhere near a concern at 40-60F.

I'm reminded of an old saying: Swallowing a camel but straining over a gnat.

 

[The Critic]

@BMWTurboDzl 's post sums it up. It really depends - the 0/5/10 ratings are empirical values that identify an oil's cold temp performance in accordance with SAE J300 standards. The oil's kinematic viscosity can vary. You'd need to test (or map) out the oil's in question to see how they compare.

For most applications it is probably irrelevant, but in certain hybrid or PHEV applications, I can see how it may make a slight difference.

 

[apollo18]

Putting the Simple Back into Viscosity - Bob is the Oil Guy

by John Sander, VP Technology, Lubrication Engineers Inc. Abstract: Simply stated, viscosity is defined as the internal resistance of a fluid to flow. That doesn’t sound too difficult, does it? Unfortunately, new temperature, speed and pressure demands on lubricating fluids have changed over the...

bobistheoilguy.com

Thx for this so this shows that 0w is thinner even at temps we assumed that 5w and 0w would be the same?

 

[kschachn]

Thx for this so this shows that 0w is thinner even at temps we assumed that 5w and 0w would be the same?

What you are seeing is entirely dependent on the specific formulation. You can’t make such a determination based on the winter rating which is only applicable for the temperature at which it’s measured.

All formulations of a particular grade are somewhat thinner or thicker than another at any random temperature. Some brands (or better, formulations) with a 0W winter rating are thicker at elevated temperatures than one with a 5W rating.

Generalizations are not warranted off that singular chart. That’s not a plot of any one specific brand or formulation. Compare for example an ILSAC 0W-30 to an ACEA A3/B4 0W-30.

 

[Kalle.J]

Thx for this so this shows that 0w is thinner even at temps we assumed that 5w and 0w would be the same?

Its a general chart, but yes. 0W30 is in most cases slightly thinner then 5W30 and 0W40 before operating temperature.

0W and 5W is basically the same at 20*C relative to how thick they are at -20*C.

 

[BMWTurboDzl]

Thx for this so this shows that 0w is thinner even at temps we assumed that 5w and 0w would be the same?

The chart shows that there's essentially very little difference in viscosity at your temp range of 50F-60F. Inside an engine there's zero difference in the speed at which the oil flows because the oil is mechanically pushed through the engine via the oil pump at a constant rate. The difference in viscosity dictates the amount of power (i.e.. parasitic drag) required to move the oil for those few seconds spent in that temperature range.

In short. 0w30 vs 5w30 is irrelevant in the Lower 48.

Remember average operating oil temps are just over 100C.

 

[DGXR]

I maintain two road vehicles, both spec 5w30 but often run 10w30 with no concerns.
Coldest winter temps are 25F, there is a very slight difference in pumpability (5w vs 10w) but it's not a problem.
As you said, the low W numbers are helpful in very cold winter temps which we do not have.

 

[apollo18]

would it also be said that a 5w oil would 'stick' to surfaces more then a 0w? albeit a very tiny bit but still some?

 

[The Critic]

would it also be said that a 5w oil would 'stick' to surfaces more then a 0w? albeit a very tiny bit but still some?

Not likely. If you are referring to film strength I don’t think a slightly higher base oil viscosity has much of an impact. Too many other variables.

 

[kschachn]

would it also be said that a 5w oil would 'stick' to surfaces more then a 0w? albeit a very tiny bit but still some?

No.

Where are you headed with all this?

 

[apollo18]

No.

Where are you headed with all this?

im afraid to say but since i am trying to learn i wont be shy
so my toyota has the 2.5l engine with vvti, and basically everyone in the world seems to have the rattle on startup for 1-2 seconds since oil pressure is low at startup. the noise dissapears within 2 seconds when oil pressure was restored. since most of these vehicles are running 0w20 i was thinking if maybe 5w30 would have a higher film strength which would lower the rattle compared to the water thin 0w20?

 

[The Critic]

im afraid to say but since i am trying to learn i wont be shy
so my toyota has the 2.5l engine with vvti, and basically everyone in the world seems to have the rattle on startup for 1-2 seconds since oil pressure is low at startup. the noise dissapears within 2 seconds when oil pressure was restored. since most of these vehicles are running 0w20 i was thinking if maybe 5w30 would have a higher film strength which would lower the rattle compared to the water thin 0w20?

They all do it. Normal for the design. If it’s excessive you can replace the VVT gear.

 

[apollo18]

They all do it. Normal for the design. If it’s excessive you can replace the VVT gear.

ty just thought maybe some thicker oil could help? it aint excessive for me just 1-2 seconds max

 

[The Critic]

ty just thought maybe some thicker oil could help? it aint excessive for me just 1-2 seconds max

I'll just say that it is entirely possible that changing brands/grade may have some impact on this behavior, for reasons that cannot be fully explained. But it is not a consistently repeatable (or reliable) way of "resolving" the issue.

 

[kschachn]

ty just thought maybe some thicker oil could help? it aint excessive for me just 1-2 seconds max

You can try it, it won't hurt anything. It's not related to the winter rating however. Try some Mobil 1 or Castrol 0W-40, it is relatively inexpensive at Walmart.

And it's not film strength, it's film thickness. Film strength isn't applicable here.

 

[Nesterenko]

They all do it. Normal for the design. If it’s excessive you can replace the VVT gear.

What most people would like to know is if the rattle is actually harmful or just worrisome and annoying.