Havoline 0W20 VI higher than 5w30 and 10w30?

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No. Simply, viscosity index means the finished oil flows well at low temperature, and doesn't lose viscosity dramatically at operating temperature. For comparison, Mobil 1 0w-20 AFE's viscosity index is 173, 5w-30 is 172, and 10w-30 is 146.
 

Whammo

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Originally Posted by ad_infinitum
No. It means that it flows well at low temperature, and doesn't lose viscosity dramatically at operating temperature. For comparison, Mobil 1 0w-20 AFE's viscosity index is 173, 5w-30 is 172, and 10w-30 is 146.
Okay, so it isn't saying that it is thicker than the others at operating temperature?
 
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Not at all. Viscosity index is a dimensionless number that represents how the viscosity of lubricant changes with temperature. The greater the viscosity index (VI), the smaller the change in fluid viscosity for a given change in temperature, and vice versa. Thus, a fluid with a low viscosity index will experience a relatively large swing in viscosity as temperatures change. High-VI fluids, in contrast, are less affected by temperature changes.
 
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For people in warmer climates, wouldn't a lower VI be a good thing? To an extent of course. It seems like most high VI oils are loaded with VII and are less shear-stable.
 
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Originally Posted by Whammo
Originally Posted by ad_infinitum
No. It means that it flows well at low temperature, and doesn't lose viscosity dramatically at operating temperature. For comparison, Mobil 1 0w-20 AFE's viscosity index is 173, 5w-30 is 172, and 10w-30 is 146.
Okay, so it isn't saying that it is thicker than the others at operating temperature?
Maybe this chart can help you understand: at 40c all the oils are the same viscosity, but as the temperature increases the oils with a lower VI lose their viscosity at a more significant rate in comparison to the oils with a higher VI. [Linked Image]
 
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Originally Posted by The Critic
For people in warmer climates, wouldn't a lower VI be a good thing? To an extent of course. It seems like most high VI oils are loaded with VII and are less shear-stable.
That, or they are blended with extremely thick and thin base oil (synthetic) and the volatility is high, leads them burnt off / evaporate away. I'd try to use 10w30 and 5w20 instead of 5w30 and 0w20 whenever possible.
 

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Or it benefits (just as a published number) from low cold flow ability - and that does not mean much to me even though I own two 0w20 spec engines … I could spend $50 gallon to get a really high VI 0w20 - but that's not going to protect my 7500 watt gen better than 15w40 at $12 gallon (would have much lower VI)
 
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Originally Posted by Whammo
Originally Posted by ad_infinitum
No. It means that it flows well at low temperature, and doesn't lose viscosity dramatically at operating temperature. For comparison, Mobil 1 0w-20 AFE's viscosity index is 173, 5w-30 is 172, and 10w-30 is 146.
Okay, so it isn't saying that it is thicker than the others at operating temperature?
You would want to look at HTHS viscosity. It represents how a fluid flows in the engine parts at high temperatures. A less useful but highly published number is KV100, or how an oil flows at 100C aided by gravity alone.
 
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Originally Posted by kschachn
No, I "reckon" it is correct. Why would you think it is not? Mobil 1 0W-20 is published as 173, well in the same range.
Guess you are too fancy and sophisticated to like the word "reckon".... LOL
 
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SR5

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Originally Posted by The Critic
For people in warmer climates, wouldn't a lower VI be a good thing? To an extent of course. It seems like most high VI oils are loaded with VII and are less shear-stable.
Yes, I think so, assuming it's well made. I'm running a full Group III synthetic 10W30 right now, and it offers me all the winter cold starting ability I will ever need, but more shear stable and lower noack volatility than an equivalent 5W30.
 
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Originally Posted by ad_infinitum
Originally Posted by Whammo
Originally Posted by ad_infinitum
No. It means that it flows well at low temperature, and doesn't lose viscosity dramatically at operating temperature. For comparison, Mobil 1 0w-20 AFE's viscosity index is 173, 5w-30 is 172, and 10w-30 is 146.
Okay, so it isn't saying that it is thicker than the others at operating temperature?
Maybe this chart can help you understand: at 40c all the oils are the same viscosity, but as the temperature increases the oils with a lower VI lose their viscosity at a more significant rate in comparison to the oils with a higher VI. [Linked Image]
Seems like the oil with the higher VI keeps its true thickness better at engine temperature, thus producing the better oil than the lower VI oil. HTHS is still the best oil spec to go by, for usefulness at temp in an engine.
 
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all specs are for "finished" oils, if we could only see what the thinner fake synthetic group III highly refined crude synthetic oils would spec at!! although there are some less shearing viscosity improvers they are generally in costlier real synthetics, no xxW20 in anything i own!! many owners fail to see past the oil caps 5-20, but the owners manual in girlfriends 18 kia optima 2.4L says 5-20 or 5-30 or 10-30 with SN or better spec + it shows a temperature chart as well. the 1/4 mpg with watery oil means little to me + if you want to go 200 thou higher viscosity oils are generally better!
 
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Originally Posted by benjy
all specs are for "finished" oils, if we could only see what the thinner fake synthetic group III highly refined crude synthetic oils would spec at!! although there are some less shearing viscosity improvers they are generally in costlier real synthetics, no xxW20 in anything i own!! many owners fail to see past the oil caps 5-20, but the owners manual in girlfriends 18 kia optima 2.4L says 5-20 or 5-30 or 10-30 with SN or better spec + it shows a temperature chart as well. the 1/4 mpg with watery oil means little to me + if you want to go 200 thou higher viscosity oils are generally better!
2011 Kia I just serviced had 5w20 conventional has 200k Neighbor just sold Expedition 368000 miles on 5w20 conventional I have worked on many high mileage vehicles with 5w20 and is reason I run 5w20 in my Grand Caravan with 10k. Oil cap and owners manual states 5w20 and if not available 5w30. Many manufacturers are going with 0w16 so I don't see a problem using oil that has been recommended for decades by multiple manufacturers.
 
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