cSt at 0C?

[jtantare]

First I want to than everyone that contributes information to this forum. I've been reading here for a couple of years. I am a Volvo driver using M1 5w40 in our 240 and 960. I just bought a stash for $4 a quart so I am set for a couple of years.

There is one thing I don't understand about oil specs. Of all the viscosity charts and oil spec charts I have found like this one, none list cSt at 0C. But by the 0W, 5W or 10W rating, we are supposed to understand how the oil will behave during cold start. We have very specific information at 40C and 100C. How can we tell the difference between a thin or thick 5W oil for example at 0 degrees C? Is there a list of specs that define viscosity at or below freezing?
Thanks for indulging my curiosity.
Justin

 

[Triple_Se7en]

Good questions... I could never understand the 40* either... much rather read the cSt at 0* and 100* for a better definition of hot & cold temps.

Who was the guy that insisted on 40*??... what's his excuse??

 

[Stinky Peterson]

Well I always heard they used 40C because that is a reasonable operating temperature for hydraulic systems. Don't know but it makes sense.

 

[427Z06]

Using a viscosity calculator and published specs, one can find the viscosity for a particular oil at various temperatures. Let me caveat that by saying that most oil are highly non-linear at temperature extremes.

Here's a chart as an example:

code:

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Delvac1 * 1300S * Delo400 * PenzLL * Rotella * Syntec * Esso XD3 * Esso XD3

T(C) 5w40 * 15w40 * 15w40 * 15w40 * 15w40 * 5W50 * 0w30 * 0w40

-20 6339 11422 13924 9125 9347 4247 2962 3767

-10 2430 3950 4581 3313 3371 1836 1250 1624

0 1066 1592 1776 1389 1406 886 595 783

10 523 729 788 656 662 469 313 415

20 282 371 391 342 344 269 179 238

30 164 206 213 194 194 164 109 146

40 102.0 123.0 125.0 118.0 118.0 106.4 71.0 94.5

50 67.1 78.2 78.5 76.1 76.0 72.2 48.4 64.3

60 46.2 52.4 52.1 51.6 51.4 51.1 34.5 45.6

70 33.2 36.8 36.2 36.5 36.4 37.4 25.4 33.5

80 24.6 26.8 26.2 26.8 26.7 28.3 19.4 25.4

90 18.9 20.2 19.6 20.3 20.2 21.9 15.1 19.7

100 14.8 15.6 15.1 15.8 15.7 17.4 12.1 15.7

110 11.9 12.4 11.9 12.6 12.5 14.1 9.9 12.7

120 9.7 10.0 9.6 10.2 10.2 11.6 8.2 10.5

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[jtantare]

ZO7 thanks for the info. Does this calculator asume that all the oils are linear?

 

[Winston]

They look linear on a logorithmic scale. Right?

 

[427Z06]

ASTM D341-93 is used for viscosity-temperature relation calculations. The VI calculations follow the method described in the Appendix X2 of ASTM D2270-93 and use Table X2.2

 

[XS650]

xW oils are speced for performance at heir lowest usable temperatures. Not many people care what they do at 0 C since that is a transitional temperature as the engine warms up.

30+ years ago the xW-xx in oil specs did refer to a their viscosity at 0F instead of the different temperatures for each xW viscisity that it does now.

The present system is much more closely tied to how oil actually performs in an engine.