Quote:
Originally Posted by bobcowan
Don't get all wrapped up in charts, graphs and numbers. They can be deceiving, unless you look up the actual test parameters. It's not as simple as drawing a line across the chart. It's a lot more complicated than that.
So Just think about it for a minute. A multi-weight oil is designed for a specific purpose. The "5W" part is thin, so it flows easily when it's cold. The "40" part is a bit thicker, so it supports the bearings, rollers, and such when the engine is hot. It's not logical for it to be the other way around. You wouldn't want something that's molasses when cold, and baby oil when hot.
Would you want to be driving around all the time with a 10W oil? Certainly not. If that were good for engines, we'd all run a straight 5W oil and be done with it. |
That's right, let's not confuse the issue with facts!! Bizarre.
What you're obviously missing - or choosing to ignore - is how temperature affects viscosity.
5 weight oil has a viscosity of 161 at 20°C / 68°F, while 40 weight oil has a viscosity of 16 at 100°C / 212°F - that means the 5 weight is 10 times thicker at 20°C / 68°F than the 40 weight oil is at 100°C / 212°F.
BTW, I've poured multi-viscosity oil in a Canadian winter - and I have personal experience that 5W30 is like corn syrup or liquid honey when it's cold.
Believe what you want, but facts don't lie.