Multi-grade oil description in wikipedia

[OilUzer]

Reference:

Motor Oil

search "Motor oil" in wikipedia, under Multi-grade section.
it says:

---
"... The SAE designation for multi-grade oils includes two viscosity grades; for example, 10w30 designates a common multi-grade oil. The first number '10W' is the equivalent grade of the single grade oil that has the oil's viscosity at cold temperature and the second number is the grade of the equivalent single-grade oil that describes its viscosity at 100 °C (212 °F). Note that both numbers are grades and not viscosity values. The two numbers used are individually defined by SAE J300 for single-grade oils. Therefore, an oil labeled as 10w30 must pass the SAE J300 viscosity grade requirement for both 10W and 30, and all limitations placed on the viscosity grades (for example, a 10w30 oil must fail the J300 requirements at 5W). ..."
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In the xW part, there is nothing about oil flow rate and pumpability!

in general, does this description pass the bitog test?

 

[SuperSalad]

It says "viscosity at cold temperature" which skims the areas of oil flow rate and pumpability. It makes sense to me and covers the topics that most often lead to misconceptions.

I like it.

 

[Artem]

Vague description at best. Needs more DATA and FACTS

 

[kschachn]

The "W" rating is an apparent viscosity which is obtained by using a Cold Cranking Simulator:

https://www.crodalubricants.com/en-gb/di...nking-simulator

Using ASTM test D5293:

https://pentasflora.com/wp-content/uploads/2014/07/D5293.pdf

This test does not measure "flow" as noted in the text.

Pumpability is assessed through ASTM D4684:

https://pentasflora.com/wp-content/uploads/2014/02/D4684-MRV.pdf

All of which is encompassed by SAE J300.

http://www.lube-media.com/wp-content/upl...motive-oils.pdf

Quote:
Two low-temperature tests are employed to define the limits of
“W” grades.

The first, low-temperature cranking viscosity is measured by
ASTM D5293 and has been found to correlate with the ability
of an engine to start at low temperatures. The test is run at
temperatures between -10C and -35C and subjects the oil to a
high rate of shearing during testing.

Low-temperature pumping viscosity (ASTM D4684) cools the
oil to an even greater degree (-15C to -40C) over an extended
period of time, designed to allow any wax in the oil to crystalize.
Such waxy materials can produce a gel preventing the oil
flowing into the oil pump and hence lead to oil starvation in the
early stages of operation in winter conditions before the engine
and the oil warm up.

 

[csandste]

Given the readership this is intended for, I think it's satisfactory. Nothing more frustrating than trying to glean some kind of basic information from Wikipedia and having an article "improved" to the point that it requires a graduate degree in the subject to understand.

 

[SuperSalad]

Originally Posted By: csandste
Given the readership this is intended for, I think it's satisfactory. Nothing more frustrating than trying to glean some kind of basic information from Wikipedia and having an article "improved" to the point that it requires a graduate degree in the subject to understand.

Exactly. It isn't a technical document for engineers. It is a reference for people who have absolutely no idea, nor any desire to know, what a CCS and pumping viscosity are.

 

[CT8]

Good enough. Marketing does the rest.

 

[Patman]

I find that the average person, even car enthusiasts I've come across on other forums, really don't understand how to interpret the viscosity number on a bottle of oil. More than once I've heard people say that a 5w30 oil means that it's a 5 weight oil when cold and then it thickens up to a 30 weight oil when hot. They don't seem to understand that oil does not get thicker as it gets hotter, it gets thinner. It's frustrating trying to convince them otherwise.

 

[OilUzer]

Originally Posted By: kschachn
...

This test does not measure "flow" as noted in the text.
...


Sounds like there is no flow rate test based on what you are saying ...

FYI:

I got the "flow rate" reference from bitog Motor oil 102 chapter:
Motor oil 102


"... Each part of the engine oil grade is based on different tests and have a different numbering system. For the first part (the cold temperature performance) it is based on the flow rate and pumpability at cold temperatures (below 32F or 0C). ... "

 

[Langanobob]

Originally Posted By: Patman
I find that the average person, even car enthusiasts I've come across on other forums, really don't understand how to interpret the viscosity number on a bottle of oil. More than once I've heard people say that a 5w30 oil means that it's a 5 weight oil when cold and then it thickens up to a 30 weight oil when hot. They don't seem to understand that oil does not get thicker as it gets hotter, it gets thinner. It's frustrating trying to convince them otherwise.

There was a technical article about oil in one of the major motorcycle magazines that said this exact thing, oil gets thicker as it gets hotter. I was going to send them an email pointing out the misconception but knowing magazine readers I figured they’d get thousands of emails and print a correction. They never did, as far as I know.

 

[kschachn]

Originally Posted By: OilUzer
Sounds like there is no flow rate test based on what you are saying ...

I don’t know, I’m not an expert on all the standardized tests for motor oil. For what little I know however, as long as it flows into to the pickup screen and isn’t gelled up for whatever reason, it’s going to subsequently flow in the engine. And that’s what ASTM D4684 aims to determine.

It definitely has to flow that far or your engine will be starved for oil in a hurry.