Liqui Moly says 5W30 flows 6x faster than 15W40 at freezing
- Thread starter OM605
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0c is 32F aka freezing. A 5wxx vs a 15wxx. Obviously the 5wxx will flow better when cold.
"Liqui Moly says 5W30 flows 6x faster than 15W40 at freezing"
I doubt 15W-40 is losing that much pumpability at a 0C. Their depiction implies this is in a running engine with a PD pump, but who knows the actual testing methods and details.
I doubt 15W-40 is losing that much pumpability at a 0C. Their depiction implies this is in a running engine with a PD pump, but who knows the actual testing methods and details.
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But wouldn’t the 15W-40 cause undo stress to the PD oil pump?
PD pumps have a pressure relief valve, so they should be fine and be able to take that condition. It could be that the increased time is also due to the pump going into pressure relief and cutting back output volume to the engine, which means it takes more time for the oil to complete all paths in the oiling system.
Cold flow here is overrated
No, it is going to be hard to compare, aside from an ILSAC 0w-30 to an ILSAC 10w-30, which will have an HTHS difference of possibly 0.1. However, we all know that the fuel economy difference isn't going to be measurable anyhow. That being said, I'm not going after SAE 30 or SAE 40 for the summers.
bobistheoilguy.com
See post #39. for exemple, if an owner's manual allows 15Wx down to -20°C and 5Wx down to -35°C, how could there be so much difference at 0°C which is way above what both oils are rated for.
+1
Stick synthetic and conventional of varying weights in glass jars and leave them outside overnight in freezing temps. A could decades ago I saw a noticeable difference when I did it.
Is it bcs. LM is Made in Germany and 15W40 is not? Trying to figure out here real reason for such performance.
That's a plausible difference when flow is powered by gravity. They obviously won't take 8 and 48 seconds to get through oil passages if pushed by a positive displacement pump.