Use Proper Terminology for SAE and API Ratings

[Drivebelt]

Weight is just a generic term in common usage that refers to grade, even though grade is the proper technical term as AEHaas has pointed out. In that sense I don't have any real problem with using the term weight. It really depends on your audience. If writing a technical paper or addressing a meeting of tribologists, then you would want to use the proper technical language grade -- but for everyday common usage, I think weight is ok. It's just another word for the same thing.

It's like if I walked into a bar to meet my friends and said … "I have a verruca vulgaris on my hallux". My friends might think .. "oh man, that's gotta be bad, is it time to get you a coffin…???". While in reality, I only have a common wart on my big toe (hallux).

Unless they were doctors they probably wouldn't understand what I just said. In this case, a more common idiom (usage of terms) would be appropriate.

When someone asks a question on a forum about a motor oil and I refer to 20 grade instead of 20 weight, I sometimes think that person might be wondering what the heck type of oil I'm referring to by calling it a grade. So, I just use weight -- everyone knows what we're referring to, tribologists and the common man.

 

[02zx9r]

Originally Posted By: Drivebelt
Weight is just a generic term in common usage that refers to grade, even though grade is the proper technical term as AEHaas has pointed out. In that sense I don't have any real problem with using the term weight. It really depends on your audience. If writing a technical paper or addressing a meeting of tribologists, then you would want to use the proper technical language grade -- but for everyday common usage, I think weight is ok. It's just another word for the same thing.

It's like if I walked into a bar to meet my friends and said … "I have a verruca vulgaris on my hallux". My friends might think .. "oh man, that's gotta be bad, is it time to get you a coffin…???". While in reality, I only have a common wart on my big toe (hallux).

Unless they were doctors they probably wouldn't understand what I just said. In this case, a more common idiom (usage of terms) would be appropriate.

When someone asks a question on a forum about a motor oil and I refer to 20 grade instead of 20 weight, I sometimes think that person might be wondering what the heck type of oil I'm referring to by calling it a grade. So, I just use weight -- everyone knows what we're referring to, tribologists and the common man.

 

[AEHaas]

I find that people are often confused because they think that "weight" and viscosity are the same. When they say "that 0w30 weight is just too thin for my car at start up. I really have to use a 5 or 10 weight to prevent start up wear. That's why I use a 10W30, just to be safe." I know they are confused.

It is my belief that using the term "grade" may be less confusing to these people. It is also proper usage and at the same time not too "scientific" to sound as a Latin medical term.

aehaas

 

[02zx9r]

Originally Posted By: AEHaas
I find that people are often confused because they think that "weight" and viscosity are the same. When they say "that 0w30 weight is just too thin for my car at start up. I really have to use a 5 or 10 weight to prevent start up wear. That's why I use a 10W30, just to be safe." I know they are confused.


I will agree with your statement on that

 

[Gary Allan]

I do agree with you, Dr. Haas. "Slang" can often be misinterpreted. G-Man often took exception to referring to a multivisc fluid as a "weight".

 

[paulo57509]

What is also confusing to me is when people refer to a straight SAE-30 but type it as "30W".

 

[DmanWho]

"Is it okay to use a 5 winter 20, in a vehicle spec'd for 5 winter 30?"

I like the way that looks!

 

[bluesubie]

Originally Posted By: paulo57509
What is also confusing to me is when people refer to a straight SAE-30 but type it as "30W".

Blackstone is one. They do refer to multi-vis oils as "multi-grade" but they refer to mono grades as "straight weights".
http://www.blackstone-labs.com/oil_viscosity.html

-Dennis

 

[TallPaul]

I have also seen "5-30." And I have seen the "5" referred ot the "front number" and the "30" as the "back number."

But what I want to know is whether we can say "SAE 30" for a straight 30 oil.

 

[AEHaas]

"But what I want to know is whether we can say "SAE 30" for a straight 30 oil."

Yes, this is correct.

 

[ravenchris]

Dr. Haas,
Thanks for the nomenclature tune-up as well as the motor oil education you made available to me.
Best Regards,
Chris

 

[ikeepmychevytoo]

SAE 30 and 30W are not terminologically the same as a monograde doesn't necessarily tested for "Winter" mark. As SAE 20 and SAE 20W-20.

 

[Audi Junkie]

Lay people confuse the winter "w" with the generic term "weight", and further mingle them into some reference to winter-weight-pusedo-term. So, maybe "grade" is a better term and it sort of hints back to what we are actually talking about- multi-grade oil. Sounds better and makes more sense than multi-weight oil.

 

[oilyriser]

Originally Posted By: AEHaas
For example, a search for 0W20 will not bring up a 0W-20 (with the dash). The correct writing is with a dash according to the standards. Despite that suggestion people have been writing it both ways. I suggest we try to be proper and use 0W-20, with a dash.


Have you tried doing a search for 0W-20, or "0W-20"?

 

[Shannow]

I reckon we should be leading the pack, and be using the proper ISO gradings....or go beyond the ISO 40 degree standard, and use visc @ 100 as the primary, and VI to describe the lower end.

Using ISO gradings, I am running an ISO 100, VI 100 in my E30...i.e my oil is 100 cst @ 40c, and VI is 100...interpolation gives me 11cst give or take at 100.

Go the other way, and describe the operating viscosity at 100C as 11, and the VI as 100....call my oil an 11-100...

Amsoil Straight 30, a 12-125

Call the oil in my diesel a 15-150...15 is the operating viscosity, 150 demonstrates that it is (as a broad brushed generalisation 50 percent better/thinner than a straight 50 at start-up.)

And most importantly, get the diff and trans oils back in the same range, rather than making the trans oils sound 2-3 times thicker than the engine oils of the same viscosity.

 

[Jim Allen]

And here I have finally trained myself to write it "5W30" and now I have to go back to "5w30." This is as bad as the uniform changes on Star Trek!

 

[02zx9r]

 

[oilyriser]

psst! hyphens mess up the search engine

 

[AEHaas]

Under "search" the first instruction says:

"Enter the criteria by which you wish to search in the form below."

Maybe the following should be added to that line:

Use 0W20, not 0W-20 for searches, no hyphen.

 

[TallPaul]

Originally Posted By: Shannow

Amsoil Straight 30, a 12-125

Call the oil in my diesel a 15-150...15 is the operating viscosity, 150 demonstrates that it is (as a broad brushed generalisation 50 percent better/thinner than a straight 50 at start-up.)


I like it! Gives you operating viscosity and an indication of how responsive it is to cold (as well as how much VII if you know the base oil).

How broad a brush is this 50% thinner at start up thing? Is it just a matter or subtracting 100? So Amsoil SAE 30 is about 25% thinner at start up than a conventional SAE 30?