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Firstly, let me get one thing out of the way. For those that blindly follow orders, please skip this post or your just going to be writing "danger will Robinson, my programming will not allow me think for myself and the manual says 0W30 so you must follow the manual". Fortunately, the Alfistas I've met are smarter than the average robot (they all drive corollas anyways), so I digress...

As you may know, the colder the weather the lower viscosity you need on the low end of the range because oil gets thicker the colder it gets. I know the recommendation in the manual says 0W30, which covers people in cold and warm weather alike, but based on what I'm reading, if you live in warmer weather a 5W30 should be perfectly fine. I'd like to put that assumption through the gauntlet however which is why I'm posting here.

So here in Southern California, it gets no lower than 45F on the coldest of mornings (it can dip to 39-40 at 5AM but I'm not counting that as I never drive at that time), and in the summer it can be 80F in the morning. I actually think a 5W30 oil will perform just the same for me, as 0W30 would for someone in colder climates. I even think I'm being generous.

Anyone have empirical data that says otherwise ?
 

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Firstly, let me get one thing out of the way. For those that blindly follow orders, please skip this post or your just going to be writing "danger will Robinson, my programming will not allow me think for myself and the manual says 0W30 so you must follow the manual". Fortunately, the Alfistas I've met are smarter than the average robot (they all drive corollas anyways), so I digress...

As you may know, the colder the weather the lower viscosity you need on the low end of the range because oil gets thicker the colder it gets. I know the recommendation in the manual says 0W30, which covers people in cold and warm weather alike, but based on what I'm reading, if you live in warmer weather a 5W30 should be perfectly fine. I'd like to put that assumption through the gauntlet however which is why I'm posting here.

So here in Southern California, it gets no lower than 45F on the coldest of mornings (it can dip to 39-40 at 5AM but I'm not counting that as I never drive at that time), and in the summer it can be 80F in the morning. I actually think a 5W30 oil will perform just the same for me, as 0W30 would for someone in colder climates. I even think I'm being generous.

Anyone have empirical data that says otherwise ?
The “cold” viscosity rating is at 100 degrees while the “hot” is reported at 212 degrees. Are you in some climate that is always in triple digits? Or is there some other research you have done that makes you more knowledgeable than the team of engineers that designed the engine?
 

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I suppose you could get away with it in a mild climate, but why would you want to? Does the thicker oil during cold start-up provide a benefit? Given the fine tolerances these engines are machined to I would think you would want maximum oil flow, which a thinner oil would help with. And I'd be concerned with violating the warranty.
 

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Well, let's assume viscosity of a multi-weight oil as a function of temperature is linear.

If so 0W-30 will at some point be more viscous than 5W-30 as temp increases because of a steeper slope. Which do you prefer?

Sent from my moto g(7) power using Tapatalk
 

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Dumb question, please educate me:

Is the bigger number the viscosity at low temp or at high temp?

It seems to me that oil is likely to be more viscous at low temp. Maybe oil is rated relative to some reference rather than with an absolute measurement?

0W oil reportedly is causal for modern engine low speed pre-ignition issues. When the oil is so thin more of it gets past rings and into the combustion chamber and some compounds in motor oil enhance pre-ignition issues.
 

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The number to the right of the W is the high-temp viscosity.
OK "the internet" says you are correct.
W stands for Winter and applies to the number to the left of W.

The two numbers are table indices, not measurements, adding to the confusion. SAE publishes a table with the translation from an actual viscosity measurement to the number that goes on the label. I presume that there are separate winter and high temperature tables.

Anyway, the viscosity of the oil changes as it wears, further complicating the original question/statement in this thread.
 

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The w is winter weight. It is cold pumping at negative 35 degrees. A 5w30 and 0w30 is identical down to negative 22c.

Interesting fact.

Pennzoil Euro LX 0w30 is actually thicker (lower pumpability) than pennzoil platinum 5w30 at BOTH 40c and 100c. So yeah, viscosity changrs over temperatures are not perfectly linear.

108251




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That said, the very important thing is to use the correct oil specification. This is the additive package the manufacturer wants you to use.

Thats SN Plus or equivalent which is API SP, ilsac gf6 or ACEA C6.

If you see freezing temps use the 0w30 too not the 5w30

Yes you're technically right that in southern California your car would have no idea if a 5w30 or 0w30 was in it
 

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Firstly, let me get one thing out of the way. For those that blindly follow orders, please skip this post or your just going to be writing "danger will Robinson, my programming will not allow me think for myself and the manual says 0W30 so you must follow the manual". Fortunately, the Alfistas I've met are smarter than the average robot (they all drive corollas anyways), so I digress...

As you may know, the colder the weather the lower viscosity you need on the low end of the range because oil gets thicker the colder it gets. I know the recommendation in the manual says 0W30, which covers people in cold and warm weather alike, but based on what I'm reading, if you live in warmer weather a 5W30 should be perfectly fine. I'd like to put that assumption through the gauntlet however which is why I'm posting here.

So here in Southern California, it gets no lower than 45F on the coldest of mornings (it can dip to 39-40 at 5AM but I'm not counting that as I never drive at that time), and in the summer it can be 80F in the morning. I actually think a 5W30 oil will perform just the same for me, as 0W30 would for someone in colder climates. I even think I'm being generous.

Anyone have empirical data that says otherwise ?
I have been running 5/30 in mine since 3 days after I bought it..(The dealership owner was driving it , it had 750 miles on it, so I changed it when I got it home)

I have experienced no problems and dont anticipate that changing
 

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Running the correct oil spec is more important than the weight, and a small change in cold weight rating is not going to grenade a motor.

However if you use an oil with lack of additives (like my 164 needs oil with a lot of Zinc in it) that the motor was designed for, that is a recipe for trouble. If you can get a 5w-30 that matches what this car needs in every other way you aren't doing any damage, though the benefits may be minor if any.
 
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I blindly follow the recommendations of the owner's manuals. Interesting thread, though.

FOR 2019 QUADRIFOGLIO:
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FOR 2018 TiQ4
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Not to discredit the conversation because I also believe it's an interesting one.. that said

I'd say some very capable people that know much more than anyone here about the subject put a lot of time and $$$ into deciding which oil is best for their engine.

For my car I'll be following their advice and using the recommended oil.
 

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The 2.0 in the Jeeps calls for 5/30....although its not a multi air...
The oil I use is SN+ and the same one we put in the turbo Jeeps so I have no fear of doing any damage.
I also recommend 5/20 to all of my clients cars that call for 0/20.... but will put in whatever they want.
 

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Discussion Starter #19
So if I was to condense all the answers given thus far, it would be that 5W30 is going to be fine for warmer temp, so long as the API recommendation is kept to the letter (additives in the oil). The smaller minority would just follow the manuel as there is concern for warantee violations, but let me reassure you that in the world of oil viscosity rating, many oils with the same viscosity rating have varying degrees of ACTUAL viscosity. If you Google fork oil viscosity chart, you'll find that some 5W are thicker than 10W oils, and in some cases even 15W. There is the same happening with automobile oils, and I can prove this by asking anyone interested to find Project Farm on Youtube. He does viscosity tests on oil all the time (there are others that do this too) comparing the flow of oil when warm and under freezing tempratures, placing two competing brands with the same ratings on a funnel to see which one flows faster, and in some cases one brand flows a LOT faster than the other how this relates to a viscosity rating preciesley is above my expertise of course, but it is 100% clear that different brands with identical ratings have different viscosities in the real world.

So there's your proof. What I would be curious to know however, is if there were any labs that did this systematically across oils, in order to put out a report we can all enjoy. Would be interesting. For now, I will likely turn to Project Farm for insight. They concluded that AMSOIL is the best brand, and of that I have no doubt, but now I'm going to check out the viscosity testing across brands for hints. I might even call the companies themselves, but ususallly you get a gate keeper programmed to read the manuel (yes yes, he or she does in fact drive a Corolla, requiste for applying for the position you see). The other aspect of the Project Farm testing that interests me greatly is the lubricity test which measures friction. Under this test, again AMSOIL performed best, but not by a lot. There were some brands that performed horribly such as Valvoline if I recall. Interestnly the Walmart Supertech oil, which is super cheap, performed increadibly well (made by Warren Oil I belive, which they also sell under a Costco brand - but only 5W30 I think).

The only reason I started this thought process was because I'm worried about waiting 10K intervals to change oil on the vehicle. I don't trust the filter to pick up all the particles that gather up, plus I have this dirty little paranoia in the back of my mind, that says the OEM isn't interested in 200K durability on their engines, and is more interested in keeping up with the jonese (marketing wise, put yourself in the mind of the guy or gal that has to come up with recommendations, and is told "Hey Tony or Toniala, BMW and Mercedes have 10K intervals, so you better suggest something that doesn't make us look bad in comparison, those houses wives only keep our cars for 5 years anywhoo, capiche ! (with a light smack on the side of the head to drive the point through lol)
 

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So if I was to condense all the answers given thus far, it would be that 5W30 is going to be fine for warmer temp, so long as the API recommendation is kept to the letter
It will be fine in colder temps also...0W oil will flow up to -30 degree Celsius while 5W will flow up to -25 degree Celsius..I dont see much difference there but I suppose the 0/w is a bit better in really cold climates...
 
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