- Joined
- Oct 21, 2015
- Messages
- 233
Speaking of physics: https://blog.amsoil.com/what-happens-if-i-use-the-wrong-weight-viscosity-of-oil/
"Brad buys a new car that requires 0W-20 motor oil. He hangs around enough gearheads to have heard the old axiom that “higher viscosity oil equals better wear protection.”"
In Brad’s case, his 15W-50 racing oil may be too thick to flow quickly enough to fill the spaces between the crank journals and main bearingswhile the engine is running.
The oil won’t form a consistent lubricating film, allowing metal-to-metal contact and wear. His engine was designed specifically to use a lower-viscosity oil, in this case 0W-20. Its lower viscosity allows it to flow faster and fill the tiny clearances between parts, leading to a durable, consistent lubricating film.
Not only that, but the engine will waste energy pumping the thicker oil, reducing fuel economy. Since thicker oil doesn’t transfer heat as well as thinner oil, operating temperatures will increase, possibly leading to accelerated chemical break down (called “oxidation“) and harmful sludge and deposits."
Sure, they are using an extreme example of someone going from 0w-20 to 15w-50, but I see lots of folks here jumping from 0w-20 to 0w-40 which is a fairly big jump, because some owners manual in some cherry picked country says its OK. w/e
"Brad buys a new car that requires 0W-20 motor oil. He hangs around enough gearheads to have heard the old axiom that “higher viscosity oil equals better wear protection.”"
Engines are Built to Use a Certain Viscosity of Motor Oil
Today’s advanced engines are built with much tighter tolerances than their predecessors. The clearances between the crankshaft journals and main bearings are tighter, for one. This is purposely done to allow modern engines to use lower-viscosity motor oil, like 0W-20 and even 0W-16.In Brad’s case, his 15W-50 racing oil may be too thick to flow quickly enough to fill the spaces between the crank journals and main bearingswhile the engine is running.
The oil won’t form a consistent lubricating film, allowing metal-to-metal contact and wear. His engine was designed specifically to use a lower-viscosity oil, in this case 0W-20. Its lower viscosity allows it to flow faster and fill the tiny clearances between parts, leading to a durable, consistent lubricating film.
Not only that, but the engine will waste energy pumping the thicker oil, reducing fuel economy. Since thicker oil doesn’t transfer heat as well as thinner oil, operating temperatures will increase, possibly leading to accelerated chemical break down (called “oxidation“) and harmful sludge and deposits."
Sure, they are using an extreme example of someone going from 0w-20 to 15w-50, but I see lots of folks here jumping from 0w-20 to 0w-40 which is a fairly big jump, because some owners manual in some cherry picked country says its OK. w/e
