Warm up for the winter

[Koz]

Actually the graph you pasted shows the opposite. The only true measurement of viscosity is the cSt listed above (called centistokes). A higher centistoke number is higher viscosity. You will notice that in each case where the temperature rose from 40C to 100C, the centistoke number went down. The viscosity did not rise.

Mark

Look at the last line for 10w-30, at 100 degrees it says mid 20 weight and at 212 degrees it says low 30 weight. Same thing for the 5w-30 and the 5w-20 shows low 20 weight @ 100 degrees and high 20 @ 212.

Koz

 

[mjuenem]

Look at the last line for 10w-30, at 100 degrees it says mid 20 weight and at 212 degrees it says low 30 weight. Same thing for the 5w-30 and the 5w-20 shows low 20 weight @ 100 degrees and high 20 @ 212.

Koz

Again, the cSt number is the actual viscosity. Any other wording added is strictly marketing-speak.

Mark

 

[Koz]

Again, the cSt number is the actual viscosity. Any other wording added is strictly marketing-speak.

Mark

The more I look the more I think You're right!

Koz

 

[mjuenem]

The more I look the more I think You're right!

Koz

Here is a link to the best over-all explaination of oil viscosity and grade terminology that I could find with a quick search. It is pretty thorough. Some good reading for everyone.

http://www.advanceautoparts.com/english/youcan/html/ccr/ccr20010101ov.html


Mark

 

[SH0ck-D]

I live in California... and it only gets to be about 40 outside at night, in sacramento that is and my 4Runner is parked in the Garage.

If you read the manual it states that the car does not need to be "warmed up" before it is driven. However, in some cases, such as in freezing and extreme temperatures, I would have to lean toward letting it idle for a couple of minutes, for reasons already stated.

To help add to the question at hand... does anyone know the thermal conductivity of generic motor oil based on weight? I think this information might be a little more helpful than knowing that it thins or thickens as it heats up.

David

 

[Koz]

Here is a link to the best over-all explaination of oil viscosity and grade terminology that I could find with a quick search. It is pretty thorough. Some good reading for everyone.

http://www.advanceautoparts.com/english/youcan/html/ccr/ccr20010101ov.html


Mark

Thanks Mark,

The link did clarify the way the unit of measure is applied to operating temp and viscosity. It seems that the info I posted was indeed accurate and does show that the oil's viscosity does increase as it gets hotter. In the explanation it states;

"SAE 30 is SAE 30 no matter what the "W" prefix number is: 0W, 5W or 10W. This viscosity in centistokes (cSt) @ 100 degrees C is with the minimum of 9.3 cSt and a maximum of 12.5 cSt."

If you look at what I had posted previously "5W-30 59.66

 

[mjuenem]

Thanks Mark,

The link did clarify the way the unit of measure is applied to operating temp and viscosity. It seems that the info I posted was indeed accurate and does show that the oil's viscosity does increase as it gets hotter. In the explanation it states;

"SAE 30 is SAE 30 no matter what the "W" prefix number is: 0W, 5W or 10W. This viscosity in centistokes (cSt) @ 100 degrees C is with the minimum of 9.3 cSt and a maximum of 12.5 cSt."

If you look at what I had posted previously "5W-30 59.66

 

[Koz]

To make the multi grade oil they start with a SAE30 oil (the higher number) and then they actually add chemicals that make the SAE30 oil flow better when cold (they stablize the viscosity so it doesn't rise as much as a straight SAE30 when cold). That is where they get the rating for the first number. These additives actually prevent the oil from getting stiffer when cold so the oil flows readily and can get to all parts of the engine quickly. But again... they start with SAE30 and it does not get thicker. It has better flow ratings in cold weather than a straight grade SAE30 would have so it APPEARS to get thicker when hot, but truthfully does not.

Mark

Mark, This is where you are making your mistake. Multi-grade oils do not start out with the higher number as its base oil. They start with the lower and add to it. Think of a 5w-30 as a 5 weight oil that will not thin more then a 30 weight when hot. I think you are confusing viscosity with flow rate. Forget about the "centistokes (cSt)" numbers.

You are right about this being a very confusing issue, I hope this helps you see what I was try to convey.

Koz

 

[mjuenem]

Mark, This is where you are making your mistake. Multi-grade oils do not start out with the higher number as its base oil. They start with the lower and add to it. Think of a 5w-30 as a 5 weight oil that will not thin more then a 30 weight when hot. I think you are confusing viscosity with flow rate. Forget about the "centistokes (cSt)" numbers.

You are right about this being a very confusing issue, I hope this helps you see what I was try to convey.

Koz

Merry Christmas!

You got me! I turned it around exactly backwords!

But look how far we came.... for the first time you said "it will not thin more than a 30 weight when hot".

That's where this whole thing started. Somebody (I forget who now) said that the multi grades get thicker when hot and that is the myth I was trying to dispel.

You even said it a couple times. But now you understand it well enough to catch me!

Have a great Christmas or Holiday or whatever - everyone!

Mark

 

[Koz]

MERRY CHRISTMAS!

Koz

 

[greasefingers]

Here is a graph that I just collected using my scanner. The ambient temperature was 38 F outside. The pink line is degrees C and the blue line is degrees F

 

[Koz]

Here is a graph that I just collected using my scanner. The ambient temperature was 38 F outside. The pink line is degrees C and the blue line is degrees F

I can't understand those figures on your graph and why centigrade and fahrenheit?

Koz