No this is incorrect. It is only guaranteed to flow at the rated temp, around -25F or so. It is not a linear relationship where 5W will flow "better" at "cold" temps than 10W and 0W is "better" than 5W. This is a very common misconception. It just refers to ability to flow for cranking purposes at extremely cold temps. That 0W oil isn't going to "get to the turbos" faster than a 10W unless it's extremely cold out.
Mobil 1 too many varieties
- Thread starter tblt44
- Start date
Because of a different base oil and VM mix. So it will flow better when it's very cold like -30F. Do you live where it gets -30F?
This is what AI says, which I have very little confidence in AI.
Oil viscosity measures an oil's resistance to flow, effectively defining its thickness and how easily it pours. Lower viscosity means thinner, faster-flowing oil, while higher viscosity means thicker, slower-flowing oil. It changes with temperature—thinning when hot and thickening when cold—making it crucial for engine lubrication.
www.castrol.com +3
Key Aspects of Oil Viscosity:
- Viscosity Grades (SAE): Oils are rated by the SAE International (e.g., 5W-30).
- "W" Rating (Winter): The number before the "W" indicates flow in cold temperatures. Lower numbers (e.g., 0W) mean better performance in extreme cold, allowing for easier starting.
- High-Temperature Rating: The second number (e.g., 30, 40) represents the oil's viscosity at operating temperature (
or
). A higher number indicates a thicker, more protective film under heat. - Multi-Grade Oils: Most modern oils are multi-grade, designed to behave differently in cold vs. hot conditions.
- Why It Matters: Proper viscosity ensures engine parts are lubricated at start-up while maintaining a protective oil film at high operating temperatures.
www.castrol.com +7
So is it better to change multi grade oil cold...that's all I asked.
Patman
Staff member
It’s better to change the oil hot because it will drain out faster and more of the contaminants will come out as well
Thanks Patman...
Well, I don't agree on that.
There is one saying:
- If it looks like a sheep, walks like a sheep and "baa" like a sheep - Probably it is a sheep.
If an oil has lower kinematic viscosity at 40*C, lower CCS, and lower MRV viscosity - Yes, it will flow better at any higher temp. than those compared to an oil with all those values higher.
What I mean:
0W-20
KV at 40*C about 45 cSt
CCS -35*C about 5,600 cP
MRV 25,500 at -40*C
10W-30
KV at 40*C about 70 cSt
CCS -25*C about 6,600 cP
MRV 17,200 at -30*C
So, CCS not only 10 degree higher temp., for 10W-30, but also 1,000 cP thicker (10 degree difference in Celsius is 18 degrees difference in Fahrenheit).
That tells me the 0W-20 oil will always flow better at any other temp. above -25*C than the 10W-30.
Values taken from HPL product data sheets:
0W-20
https://www.hplubricants.com/wp-content/uploads/2021/08/PC-Premium-Engine-Oil-PDS.pdf
10W-30
https://www.hplubricants.com/wp-content/uploads/2021/08/PC-Engine-Oil-PDS.pdf
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Right now best 0W-20 for the money in Walmart are:
Mobil 1 Euro ESP
Castrol Extended Performance (golden jug)
So those will serve you more than well, if you cannot find Pennzoil Ultra Platinum. I think they are better oil than the Pennzoil as well.
It's all about shelf space. The more varieties, the greater the shelf space.
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Mobil 1 should make a short interval oil (for the people that insist on changing it every 3,000). Rebadge their EP lineup and call it…Mobil 1 SI…and jack the price up $3.
Mobil 1 SI (short, for short intervals)
Mobil 1 SI (short, for short intervals)
Patman
Staff member
Jack the price up and tell everyone it’s for short intervals? That seems like a sure fire marketing failure
4wd
$50 site donor 2026
Warm guy myself - not burning myself over extreme views
4wd
$50 site donor 2026
I agree since I go to Walmart and can seldom find Mobil 1 Supercar in the 40W or 0-20 Mobil 1 hybrid oil. I thought I grabbed 2 bottles of 0w20 hybrid for my Maverick but grabbed the 0w20 in the ESP instead but I am just going to run it. Way too many variations and the stock boys and managers probably are unaware of the best sellers since they are out of stock most of the time. Problem is the price is much higher in some of the smaller auto parts stores.
OVERKILL
$100 Site Donor 2021
Assuming a PD pump, as long as the pump isn't on the relief, both oils will flow the same, as the pump will move the same volume of oil per rotation regardless of the visc.
O.K. PD (positive displacement) oil pump moves the same amount of oil (regardless of its viscosity) but how fast the oil travels after that? Doesn't it depends on the oil viscosity?
For example if we pump at the same psi (with PD pump) water, then syrup, then honey in particular pipe diameter they will have different path length in that pipe because have different viscosities. We know higher viscosity has higher drag or resistance.
Will it be the same lubrication because the pump is PD?
OVERKILL
$100 Site Donor 2021
What parts are oiled "after that"? Bearings, cylinder walls, pushrods/cups, rockers, cam gears/chains, these are all pressure fed. The pipe analogy doesn't really work, because the pipe you are describing isn't fully enveloped, where the gallery system is, with small offshoot paths where the fluid ultimately ends. If you dump 1L of fluid in your pipe, there's 1L of fluid, regardless of whether it's water, syrup or honey, they will pool or spread-out differently, because you aren't filling the pipe, but the volume is the same.
As long as the oil can get back to the sump (the only real part of the process dictated by gravity) quick enough to prevent the pick-up from being exposed, and the oil is able to be drawn in the pick-up, it doesn't really matter.
But my point was more in addressing this:
Japanese said:
Which is simply wrong, as long as the pump is not on the relief. The same volume of oil is being moved through the engine; the flow rate is the same.
Plus the fact that “flow” never lubricated an engine and never will.
Flow is the most important oil property. Without a proper flow the oil cannot lubricate. Hence why its KV, CCS, etc. properties are measured to establish its suitability for particular application.
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