0W vs 5W vs 10W viscosity curve?

ZeeOSix

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A linear y-axis scaled to include the highest viscosity on that plot would make the lowest ones difficult to distinguish from each other---and from zero.
True, but OP was only really focused on very cold temps.
 
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I've also been wondering about temperature and how it relates to the winter numbers on oil. My mother's vehicle - the Envoy listed in my sig - has a rather large oil usage issue. Due to financial limitations, it's anyone's guess as to when we will either be able to repair it or replace the vehicle altogether. My place of work - Advance Auto Parts - sells Chevron Delo 400 SDE and other HDEO oils with the SN spec in the 15w-40 variation in a gallon size for $20, which I can get for $16 with my employee discount. Or in 2.5-gallon sizes for $32 or $28.60 with the discount. I'm running this as it will be cheaper in the long run rather than the 5w-30 that is called for.

My concern is when it hits winter here in WI, it can get down to -30F. I'm concerned that running a 15w oil can cause damage to the engine at low temps like that because the pump will not be able to get it to the critical engine parts in time when it is that cold. At least, this is what I've read on other forums. What are the thoughts you all here have on this?
I've run the numbers on the Lucas stabilizer, which is basically a thickener. You are slowly destroying engines. If I remember, it took a 10W-40 to a 20W-50 on a normal capacity engine. So you are getting very poor lubrication and high wear on every startup, at every temperature.

And running a diesel oil in a gasoline engine will destroy modern catalytic converters. By API rules, you can tack an SN or SP onto the end of any diesel formulation that meets the wear and other characteristics, ignoring the high phosphorous content. This sort of makes it ok for fork lifts and other equipment. That is why it (even in a 10W-30 viscosity) will never have an ILSAC starburst.
 
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I've run the numbers on the Lucas stabilizer, which is basically a thickener. You are slowly destroying engines. If I remember, it took a 10W-40 to a 20W-50 on a normal capacity engine. So you are getting very poor lubrication and high wear on every startup, at every temperature.

And running a diesel oil in a gasoline engine will destroy modern catalytic converters. By API rules, you can tack an SN or SP onto the end of any diesel formulation that meets the wear and other characteristics, ignoring the high phosphorous content. This sort of makes it ok for fork lifts and other equipment. That is why it (even in a 10W-30 viscosity) will never have an ILSAC starburst.
I don’t know about the Diesel engine oil in gas engine. The Harvest King VOA’s I did and rotella ones aren’t as stout as they used to be. I believe oil burning vehicles will destroy a cat converter before running a HDEO in the vehicle. Maybe I’m dumb or…..
 
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my oil eating 72 Nova with the 307 would barely crank with conventional Valvoline 20-50 with colder Pa weather around 30F + my garaged 2008 sportster would NOT crank fast enough to start with Amsoil 20-50 supposedly synthetic in early 2000 in my 50 degree garage but 10-40 made it like summer
 
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