Pour Point Vs. Viscosity

[byez]

I have been playing around quite a bit with the viscosity calculator at Esko.

I was comparing Mobil 1000 5w20 vs. Esso XD3 0w30.

Mobil 1000 5w20
cSt at 40°C 46.7
cSt at 100°C 8.4

Esso XD3 0w30
cSt at 40°C 71
cSt at 100°C 12.1

So here is where I am confused. The Mobil 1000 is a 5 weight while the XD3 is a 0 weight. So the 0 weight should have a lower viscosity at low temperatures? According to the calculator, the 5 weight has a lower viscosity at -10,-20,-30,-40°C. Am is missing something here?

To further complicate things, the Mobil 1000 dyno has a pour point of -30°C while the XD3 synthetic has a pour point of -48°C. How can a lower viscosity product have a lower pout point than one that is much thicker at temperature extremes?

I am still unsure of what to make about CCS & MRV. Could someone also throw these into the big picture and explain how viscosity, pour point, ccs, & mrv contribute to making a good winter oil.

 

[MGregoir]

The numbers from the Esko calculator are kinematic viscosity, instead of dynamic which is the Cold Crank Simulator and MRV pumpability tests.

CCS and MRV is used to determine the Winter grade of the oil. A 5W oil must be less than 6600 centipoise in the cold crank simulator at -30, and 60000 centipoise at -35 in the MRV cold pump test. These numbers tell the real story about cold performance. 0W is better than a 5W oil as it must perform better than a 5W oil performs at -35 at -40.

Dynamic viscosity, how well the oil pumps, rather than kinematic viscosity which is how well the oil flows.

Pour point is based on how much the oil thickens and kinematic viscosity (the centistoke numbers) to an extent, but it is caused by the chemical characteristics of the oil. Oils are based on parrafinic base stocks, and the more heavily de-waxed and saturated the hydrocarbons in the base oil, the better the pour point. There are also other chemicals that can be added to inhibit the formations of these wax crystals as the oil gets colder, which is what greatly effects pour point. PAO and esters generally have better pour points as they are synthesized, then group III oils because they are most heavily saturated (the higher the viscosity index of the base oils, generally the lower the pour point), then group II+ and group II oils. A better oil will generally have a better pour point.

BTW, Mobil Super 1000 is not worth the money relative to just about any other oil you can get off the shelf. They want Pennzoil price for Esso Extra product, IMHO. You are paying for it to come in a really pretty jug.

 

[marcel]

If you don't mind a 40 wt. the Petro Canada Duron E 0W-40 has the lowest pour point of any oil, -66 C.

 

[addyguy]

MGregoir,

Gotta respectfully disagree on your point about Mobil 'Super 1000 (& 2000)' oils. Although I have no proof, I think these oils are slightly higher quality than regualr Esso Protec. Although Protec is a great oil, I think you will find these 'Super' oils are closer to add-pack and composition of Mobil Clean 5000 & 7500 oils, which have shown some really, reallt good UOA's on this board.

JMHO

 

[byez]

Actually I picked up a 5 litre jug of Mobil 1000 for around $12 on sale at Part Source. I couldn't resist. I might just use it for the summer and go back to synthetic in winter.

Thanks for clearing everything up MGregoir.

 

[MGregoir]

I guess, but all things considered I can go buy 4.73 litres of Pennzoil for no more than $16.99 most places, and as little as $9.98 on sale. The Mobil Super 1000 is probably a good oil, maybe a little better than Extra, but for the price I don't think it's any bigger than the yellow bottle which is a known quantity.

I just can't see Canada being a big enough country to permit two products in the same space from the same manufacturer.

I would almost be willing to go buy a bottle of Extra 5W-30 and pay for a VOA on it if you were willing to do the same with a bottle of Super 1000 5W-30 at the same lab to compare notes.

I would say the Super 2000 is a better oil, but the value proposition on the Super 1000 is off.

 

[mechtech2]

40 deg C is not really cold, but middle warm. At O def F is where the oil's low temp rating is accurate.
In between temps will vary.