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Quote:

Originally Posted by Bonburner (Post 3150020)

You may also be misunderstanding the ranking of the first value (0W). It is not a measure of how much volume flows for a set distance * time. It is the necessary force (cP) that must be applied to the oil in order for the oil to move a set distance * time. This is important because it shows that the oil pump is capable of pushing the oil up and begin the lubrication process when cold, but it does not able to display how well the oil natively flows overs all the internal parts (as shown in cSt - which is what the set of 3 graphs show).

So look at back the at the SAE chart and you'll see that the simple requirement to be 0W weight is to have ≤60k centipoise at -40°C at the pump and ≤6,200 cP at -35°C cold crank simulator.

The difference between that and 5W isn't too far off: pump force ≤60,000 cP at -35°C and ≤6,600 cP at -30°C.

For argument sake compare a 0W-40 to a 5W-20. If I understand this correctly a 0W will be picked up by the oil pump easier than a 5W but not necessarily flow better through the engine at a given temperature.

This link to a BITOG thread discussing MRV and CCS is relevant here although I'm still trying to digest it. From what I gather from reading it kinematic viscosity is irrelevant at cold temperatures.:confused0068: https://www.bobistheoilguy.com/forum...Number=1836257

Quote:

Originally Posted by cueball89 (Post 3150037)

Unfortunately, Mobil1 doesn't provide 5W-20 cold pump nor cold crank cP. So we can't really compare the two weights. **Edit: even if we did, they would be reported at different temperatures so we can't REALLY make a direct comparison.**

But I want to add that there is the technical possibility that a 5W CAN (albeit unlikely) have a lower cP than 0W because the weights are dictated by a maximum cP at a given temperature. So, if a 5W just happens to have a 50,000 cP at -40°C versus a 0W oil at 55,000 cP at -40°C.

But yes, the cold crank and pump is more important than the kinematic viscosity in the cold, but kinematic is still important. Oil still needs to be able to flow and seep around parts in the engine.