Mixed 10w-30 w/ 5w-30!!@$%

[blood]

The reason 5w20 is recommended in the US is to meet CAFE regulations. The same motors in Australia are spec'd to run 5w30. I've run 0w30 in mine since day one and the valvetrain is much quieter.

This is also true but tolerances were set tighter when the standard was changed.
No matter what,the way oils are today you will never have a issue if you use a quality oil .

 

[Icecobra]

Well the facts for oil are really tight today. Back in the day we ran 30w its what we all had its what we all used. Mulit-viscosity oil came along and its designed for the first number with the w for lowest temperature viscosity (means flows more like water). As it gets hot it thickens hence the second number. Our trucks have very close tolerance and although it will flow, just thickens more if its 30 instead of 20. Meaning your flow rate for how fast oil gets in and out of bearings, cams, rods, and the like its going to take longer , get hotter and have more build up. So the long and short of it is to run the correct oil. In the case you mix one quarts of 10w30 with 5 quarts 5w20 the damage or change to the viscosity is negligible. There are two ways in which oil viscosity is measured: single grade and multi-grade. SAE 30 is a typical single-grade rating. That means that an organization called the Society of Automotive Engineers (SAE) ran the oil through a standardized tube-like device and timed how long it took, in seconds, to flow from one end to the other. The viscosity rating is the number of seconds rounded to the nearest multiple of ten. Thus, SAE 30 oil takes approximately 30 seconds to flow through the tube. This single viscosity rating is sometimes called the oil's "weight."Unfortunately, oil changes its viscosity with temperature and the single viscosity rating only represents the flow of oil when it's warm. What if you need to start your car on a cold winter morning? The oil will flow more slowly, so the cold viscosity rating is important too. A multi-grade rating gives you both the hot and cold viscosities. For 10W-30 oil, the 30 is the same as the SAE 30 viscosity rating for warm oil, but the 10W is the viscosity rating for cold oil, according to a standardized rating system developed by the SAE for winter oil use. And that’s more than you wanted to know about oil….

 

[The Car Stereo Company]

huh?

 

[Fred]

Did not know that...good info....

Busa to much reading for you?


Sent from iPad 3 using Tapatalk

 

[Mjolnir]

So I get the 30 on the 10W-30 rating, but can you explain the 10 part again. It's the rating for cold, which means the oil would be thicker, flow less rapidly. If it's the same measurement criteria as the SAE 30 rating, wouldn't the number be higher as when cold it would take it longer to get through the tube, or are we talking two different tests?

Well the facts for oil are really tight today. Back in the day we ran 30w its what we all had its what we all used. Mulit-viscosity oil came along and its designed for the first number with the w for lowest temperature viscosity (means flows more like water). As it gets hot it thickens hence the second number. Our trucks have very close tolerance and although it will flow, just thickens more if its 30 instead of 20. Meaning your flow rate for how fast oil gets in and out of bearings, cams, rods, and the like its going to take longer , get hotter and have more build up. So the long and short of it is to run the correct oil. In the case you mix one quarts of 10w30 with 5 quarts 5w20 the damage or change to the viscosity is negligible. There are two ways in which oil viscosity is measured: single grade and multi-grade. SAE 30 is a typical single-grade rating. That means that an organization called the Society of Automotive Engineers (SAE) ran the oil through a standardized tube-like device and timed how long it took, in seconds, to flow from one end to the other. The viscosity rating is the number of seconds rounded to the nearest multiple of ten. Thus, SAE 30 oil takes approximately 30 seconds to flow through the tube. This single viscosity rating is sometimes called the oil's "weight."Unfortunately, oil changes its viscosity with temperature and the single viscosity rating only represents the flow of oil when it's warm. What if you need to start your car on a cold winter morning? The oil will flow more slowly, so the cold viscosity rating is important too. A multi-grade rating gives you both the hot and cold viscosities. For 10W-30 oil, the 30 is the same as the SAE 30 viscosity rating for warm oil, but the 10W is the viscosity rating for cold oil, according to a standardized rating system developed by the SAE for winter oil use. And that’s more than you wanted to know about oil….

 

[Icecobra]

So I get the 30 on the 10W-30 rating, but can you explain the 10 part again. It's the rating for cold, which means the oil would be thicker, flow less rapidly. If it's the same measurement criteria as the SAE 30 rating, wouldn't the number be higher as when cold it would take it longer to get through the tube, or are we talking two different tests?

Nope you have it backwards the cold rating is its thinner as it warms up it gets thicker, help in cold start situation.... Thats what the w in multi weight means at 0 degrees it flows like 10 weight oil so in the little tube it flows 10 seconds to the other end and thickens as it gets hotter to 30 weight....

 

[Fred]

Nope you have it backwards the cold rating is its thinner as it warms up it gets thicker, help in cold start situation.... Thats what the w in multi weight means at 0 degrees it flows like 10 weight oil so in the little tube it flows 10 seconds to the other end and thickens as it gets hotter to 30 weight....

I need a cheat sheet...my wife's Audi calls for 0-20, the dealer uses Castrol, they call it a Eurpoean Formula or something...I never really paid much attention until now

 

[Icecobra]

I need a cheat sheet...my wife's Audi calls for 0-20, the dealer uses Castrol, they call it a Eurpoean Formula or something...I never really paid much attention until now

Its easy to follow. 0w20 is 0 weight in the morning when its cold, 20 is the weight when the engine is at normal operating temperature. So back to the tube again 0 takes 0 seconds to flow through the tube cold, like water. 20 it takes 20 seconds to flow through the tube. The complex chemical makeup of oils today means they work better and last longer than oils of 30 years ago. Hope this helps...

 

[Blind1]

Then why in the old (70s - 80s) days, at least down in the Southeast we were told to run 20w-50? Other words why has it changed so much?

 

[Icecobra]

Then why in the old (70s - 80s) days, at least down in the Southeast we were told to run 20w-50? Other words why has it changed so much?

The changes in oil makeup and the very close tolerance used to day to make things versus 20 to 30 years ago. Today we have better measuring tools and can measure things to .00001 of an inch using laser and optical recognition technology Thats why electronic things are smaller better faster than 20 to 30 years ago... Progress.... So tighter tolerance requires better faster lighter and more specific oils. Most oil additives today you see are really a waste of money and can tend to actually cause more problems than help....