0w vs 5w in a typical winter.... Does it matter?

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7,218
Location
Michigan
I live in Michigan and have Michigan Winters. These are usually 20's-30's with occasional teens or even around zero.

I can see an advantage of a 0w in every cold weather, but is there really that big of an advantage in normal winter weather?
 
Messages
16,132
Location
NE,Ohio
a 0w20 vs a 5w40 sure (some cars spec both)

a 0w30 vs a 5w30 not really. maybe a fraction of a mpg better when warming up (driving)

What little bit it matters can depend on the oil. there are viscosity ranges within the oil grade too.
 

ZZman

Thread starter
Messages
7,218
Location
Michigan
Any 0W rated oil will only be guaranteed to be thinner than the comparable 5W rated oil below around -35F or so. Are you starting unaided at that temperature?
No. And rarely would we get in the negative teens. And that's where a lot of the cold pour tests that you see are misleading. They show them at super cold temperatures instead of what typical temperatures people see. They should do the test like it 0 degrees.
 
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17,886
Location
...
The problem with your question is that in places like Michigan the weather can turn very cold quickly.

So if you are running a thick oil and suddenly the temps drop to below zero you have to run out and change it?

For most people no matter where they live, it’s the actual grade that matters, not the W rating. Nobody has a problem running 0wxx in mild temperatures.
 
Messages
18,066
Location
Upper Midwest
No. And that's where a lot of the cold pour tests that you see are misleading. They show them at super cold temperatures instead of what typical temperatures people see. They should do the test like it 0 degrees.
The rest of the winter ratings such as 10W and 20W are applicable at those temperatures. No "cold pour tests" are needed, they are just for Internet theatrics.

On the other hand "pour" isn't really the problem, cranking and pumpability is. The two ASTM tests in SAE J300 address that. You should always chose an oil with a winter rating that is appropriate for your expected starting conditions since that is the most accurate representation of the behavior of the oil in cold(er) temperatures.
 
No. And rarely would we get in the negative teens. And that's where a lot of the cold pour tests that you see are misleading. They show them at super cold temperatures instead of what typical temperatures people see. They should do the test like it 0 degrees.

Not misleading, it's up to you to know what the parameters are. Typical temps for someone in Wyoming are a lot colder than someone in Tennessee. You've decided the test temp should be 0. Sounds like a good project for you. (y)
 
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3,922
Location
WI.
you get a cold winter going then L. Superior freezes +80% the potential for -30F or even -40F is there... and when the bitter cold rolls in it usually sticks around, that why you use 0WXX. I have witnessed Polar Vortex myself more than a few times.
 
Messages
18,365
Location
NH
My cars don't beat on, they are easy on oil, so whatever difference there is between 0W and 5W is probably not saving anything (shear or whatever). 0W has less drag at lower temps, and from what I can see, costs the same at Walmart. I might not "need 0W" but if it the engine doesn't care...

That said I tend to just dump 5W30 into everything. :)
 
Messages
444
Location
FL, USA
So, in regards to pumping in most cases in the US there is no practical difference between 0W and 5W.
But that doesn't mean the viscosity is equivalent through the entire warm-up range.
The viscosity at 100C should be the same. But the viscosity from 0-40C is going to be lower for 0W vs. 5W.
Do you think your motor oil goes from ambient to operating temperature in no time? No it takes 5-15min depending on many factors.
Also, 0W will often times have slightly lower HTHS. So, even at operating temperatures 0W should be more efficient.

The difference in efficiency at operating temp is probably negligible.
But the colder the climate means that the time the engine/oil stays at relatively cold temperatures longer.
So, there will be a real difference in efficiency, that you still might not notice, but its there.
 
Messages
792
Location
Alberta
I run M1 AFE 0w30 in our short tripped '07 K24 Accord. It occasionally sees -30C starts without being plugged in, as my wife doesn't have access to an elec outlet at work. In those cold snaps she usually leaves the car at home and catches a ride with me. But when that can't happen due to schedules, I like having a 0w__ oil in the sump.
 
Messages
3,147
Opinions are great, but the only way to be sure is to test it out for yourself.

From my experience -- going from the positive teens down you'll notice a difference using a 0w vs a 5w.

What is the "difference" you experienced?
 
Messages
11,746
Location
Illinois
Opinions are great, but the only way to be sure is to test it out for yourself.

From my experience -- going from the positive teens down you'll notice a difference using a 0w vs a 5w.
But what difference are you noticing, weak battery or harder to pump oil?

Without actually testing, you don't know what you are experiencing.


Not sure the testing is worth the effort for most of us as it's largely been done by the auto makers. Just use what they say to use and 99.44% of us will be fine.
 
Here are two excerpts from the owners manual of a 2013 and a 2014 Chevy Silverado. In 2013 Chevy recommended 5w30 but if ambient temps went down to -20 F, they recommended using a 0w30. In 2014 the 5.3 and 6.2 V-8’s were redesigned and they went to 0w20 for year round use. This may have been due to CAFE or whatever, but they were not afraid to spec a 0w for year round use.

Going back to 2013, they thought -20 F was a good time to switch to 0w. Anything above that, the differences are small. I am running 0w30 in my Burb, but I will see a few -20 F starts after cold soaking all afternoon sometime during this winter.

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