I had a bunch of straight 30 and straight 40 weight oil once. I ran the SAE 30wt in the "winter" here, and SAE 40wt in the summer months. So even a 10w-xx is not necessarily needed.
any reason not to use a 10w in the south with hot temperatures year round?
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I would skip most 10W oils simply because they are not the R&D focus of anyone. Mobil's best, for example, is not going to be a 10W anything. A 5W-30 should be robust enough for most cases. Maybe if you are talking about a 40, 50, or 60 there could be advantages.
Best for what?
As far as protection goes, and higher ZDDP content, Mobil themselves recommend 0W40 or 10W40 HM. So I think there are plenty of users for any grade, which is why Mobil still offers a wide range from 0W16 to 15W50 at most stores.
That's a good point as well. The chemistry in the Mobil 1 EP grade should be the same though, I would think, compared to the other grades. I was going to run M1 EP 10w30 through winter just for the heck of it knowing it may contain less VIIs. The flash point is noticeably higher in that particular grade too, which I though was interesting (although mostly likely meaningless).
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Still a modern SP … just not dexos 1.3 unless 0W20 or 5W30 …
0w grades always have better base stocks. Here in AZ where the temps get 115 almost everyday, I run 0w40 most of my cars year round.
Vii get broken down not just by heat but chemically by fuel dilution.
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The difference in startup viscosity between 5W-30 and 10W-30 is about 16°F... meaning 5W-30 at 30°F is the same viscosity as 10W-30 at 46°F.
The advantage of using a thicker grade is there is less VI (viscosity improver) additive in the mix. That means there is more lubricant, because VI improvers don't lubricate, they just make the oil thicker.
Pros and cons.
The advantage of using a thicker grade is there is less VI (viscosity improver) additive in the mix. That means there is more lubricant, because VI improvers don't lubricate, they just make the oil thicker.
Pros and cons.
I’m in Canada, though not a super cold part. I’ve used 10w30, 15w40, straight 30, and 20w50 in gas engines for 10’s of thousands of km for each grade, with no ill effects. Used to run 20w50 below freezing and it was fine.
ahah i was hoping that a 10w oil would be thicker. kinda like if we coat a aluminum baking pan with water vs if we coat it with an oil. the oil will stick to the pan more then the water and provide more of a cushion compared to the water.
so i was hoping a 10w oil since it is thicker would provide more cushion for the parts compared to a thinner 0w oil but don't think there really is a drastic difference in that property
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So what would you think the coldest temperature you would be comfortable running a 10w-xxx oil - for curiosities sake?
Perhaps when engines start having aluminum baking pans and water in them.
All 10w-XX oils will perform perfectly at least down to freezing 32 deg. That's an easy rule of thumb to remember.
A good rule of thumb:
Never never never compare or correlate anything that happens outside of a running engine with what happens inside a running engine.
No baking pans, no pressure tests on oil coated ball bearing, on oil dripping down a glass surface, just no no no don’t do it .
10 W- x should be good to -25 C (-13 F), but I use 0w30 from Dec 1 until spring. Regarding VI issues take notice how many high performance oils are out there that are 0w40 including oil recommended for the Corvette and Challenger.
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Of course. 10w-oils can go MUCH lower than freezing, but I though it was an easy rule of thumb to remember.
Most owners manuals I have seen show 10w down to ambient temps around 0 degF.
I personally feel comfortable running a 10w at consistent lows down to about 15 degF or so. If I plan to operate a vehicle consistently at temps less than that, then I would go with 5w or 0w.
I personally feel comfortable running a 10w at consistent lows down to about 15 degF or so. If I plan to operate a vehicle consistently at temps less than that, then I would go with 5w or 0w.
Usually this hypothesis is phrased like, "it doesn't matter how fast the oil gets there if it never left in the first place."
The fault within the hypothesis is associating the the cold performance (winter rating) to how much stayed on parts when the engine is parked, and then got cold.
When I park my engine, it's hot. The hot characteristics of the oil would determine how readily it moves back to the sump, vs staying in/on bearings, cams, lifters, chains, pins, rings, etc.
This concept was the selling point for old additive products like STP. The mechanic would dip the shaft of a screwdriver in some STP and then ask you to hold it by pinching it.
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