why dont manf. show temps for the weight?

[jocktheglide]

im curious as to why oil manufacturs dont show their temps to weight or something? such say:
5 weight = -30F
30 = 30 F

50 = 400f

something along those lines? wouldnt that make picking an oil easier based on your enviromnet, upgrades on car, etc...?

how can the same spec in the U.S. for a car that saids it needs 5w-20 in main be the same as in 5w-20 in arizona? when the heat exceeds 105 on average 2 to 3 months out of the year???

 

[Gary Allan]

People already don't know what the current designation means. Why further the confusion by putting -30 on there? If they're in a -10 environment, they'll sensibly (not) buy an oil that displays -20 or whatever. There's plenty of usable data they could put on the label, but I don't see anyone outside of BITOG (and like communities) needing the added complexity. Our public needs A, B, C, D.

Select a motor oil that displays "A". I guess we already have that. SL, SM, etc..etc.

 

[jocktheglide]

Originally Posted By: Gary Allan
People already don't know what the current designation means. Why further the confusion by putting -30 on there? If they're in a -10 environment, they'll sensibly (not) buy an oil that displays -20 or whatever. There's plenty of usable data they could put on the label, but I don't see anyone outside of BITOG (and like communities) needing the added complexity. Our public needs A, B, C, D.

Select a motor oil that displays "A". I guess we already have that. SL, SM, etc..etc.


good points there just add to the confusion....

 

[jpr]

* Because the oil viscosity requirements are based upon the engine design and there is no absolute and independent relationship between ambient temperature and viscosity requirements.

* Because the cooling systems in modern engines are really pretty good and the operating temperature of the oil does not typically vary too much regardless of the ambient temperature.

* And for what it is worth, it is actually possible to find a 0W-20 oil with a higher viscosity than a 5W-20 oil at operating temp. In which case the 0W-20 whould arguably be the better choice for operating in high ambient temperature conditions.

 

[jocktheglide]

I dont believe the first one you posted since if you look at the same car and in europe they use a higher viscoity than the U.S......you can use 5-30 here in the u.s. and that the recommended, but if you bring your car overseas and bring into the dearlship they will put in something totally different such as higher viscoity of 5-40 if not 15-w50. they dont change the engine spec for the same car in the U.S. vs europe last time I checked.....for example another one....you can have an FJ cruiser in africa and they use 15w-50 in the same 4.0L engine vs what it specs here in U.S. at 5w30......I just read info. on CAFE.....which is political driven in the U.S. to improve mpg on vehices thats why its recommened majority on cars 5w-20 or 5w30.


Originally Posted By: jpr
* Because the oil viscosity requirements are based upon the engine design and there is no absolute and independent relationship between ambient temperature and viscosity requirements.

* Because the cooling systems in modern engines are really pretty good and the operating temperature of the oil does not typically vary too much regardless of the ambient temperature.

* And for what it is worth, it is actually possible to find a 0W-20 oil with a higher viscosity than a 5W-20 oil at operating temp. In which case the 0W-20 whould arguably be the better choice for operating in high ambient temperature conditions.

 

[jpr]

So you believe oil viscosity requirements are independent of engine design?

 

[jocktheglide]

Originally Posted By: jpr
So you believe oil viscosity requirements are independent of engine design?

do you?

 

[jpr]

Originally Posted By: jocktheglide
Originally Posted By: jpr
So you believe oil viscosity requirements are independent of engine design?

do you?
hmmm...
Originally Posted By: jpr
* Because the oil viscosity requirements are based upon the engine design and there is no absolute and independent relationship between ambient temperature and viscosity requirements.

 

[jocktheglide]

not starting a fued, but what are your reasonings? not just because the manufacture recommended it either reasoning...how do you know the joe blow didnt rebuild his engine to race it would you still recommend the same viscoity? why dont all reacers use 5w-20 or the 5w30? I can follow the manufactures recommendations also and register and tell everyone:

-what does your manual say?


Originally Posted By: jpr
Originally Posted By: jocktheglide
Originally Posted By: jpr
So you believe oil viscosity requirements are independent of engine design?

do you?
hmmm...
Originally Posted By: jpr
* Because the oil viscosity requirements are based upon the engine design and there is no absolute and independent relationship between ambient temperature and viscosity requirements.

 

[jpr]

Tell you what Ace, I'm lazy.
How about you do a little research and see if you can learn the answer to own question -
Originally Posted By: jocktheglide
how can the same spec in the U.S. for a car that saids it needs 5w-20 in main be the same as in 5w-20 in arizona? when the heat exceeds 105 on average 2 to 3 months out of the year???

Have a nice day.

 

[Quattro Pete]

Originally Posted By: jocktheglide
why dont all reacers use 5w-20 or the 5w30?

Doesn't NASCAR use 0w-20?

 

[Quattro Pete]

Originally Posted By: jocktheglide
im curious as to why oil manufacturs dont show their temps to weight or something? such say:
5 weight = -30F

Because it's not as simple as that. Not all 5-weight oils have the same minimum pour point.

Besides, even if you live in Arizona, you can benefit from running a 0w30 oil as opposed to 10w30. Cold start refers to an engine that has cooled below its normal operating temperature - it could be 80F, and it would still be considered cold start. Depending on the composition, a 0w30 may still flow better at 80F than a 10w30 will.

 

[1999nick]

Do not forget that, in the US, the owner's manuals have to specify ONLY the oil weight that was used to obtain the fuel mileage stated on the window sticker. Actually, most engines would perform in practically identical fashion if we used many different weights of oil.

For example, the owner's manual from my 1980 Pontiac Bonneville allows oil weights of straight 30, 10W30, 10W40, 20W20, 20W40, 20W50, straight 10W, 5W30, and 5W20; all recommended at various temperature ranges. I'm sure it would have included the various 0Wxx weights if they had been available then.

Plenty of people have successfully used thicker oil than 5W20 in their engines where it is recommended with no bad effects; probably no advantage to the thicker oil, but no harm done.

 

[Gary Allan]

Quote:
I dont believe the first one you posted since if you look at the same car and in europe they use a higher viscoity than the U.S......you can use 5-30 here in the u.s. and that the recommended, but if you bring your car overseas and bring into the dearlship they will put in something totally different such as higher viscoity of 5-40 if not 15-w50.


That can be due to many reasons that have nothing to do with the visc per se~.

Let's say you're in land where the typical OCI from the OEM spec's 5w-40 and 1 year? Note that Ford and other domestics gravitate toward 5k+/-.

That is, the market just isn't wrapped the same way as it is here.

Take Oz. Now its obvious that you can use 5w-20 in Death Valley ..blah-blah-blah ..but if no one sells the stuff in Oz ..just what do you think the OEM spec will be for an "imported domestic"?

I see it as another form of many of the immutable triangles that typically form around processes. If you want higher output capability with long drains (and a few other hoops that the Euro's pull out of their behinds on a routine basis) ..you spec a 5w-40 and make it even jump through hoops.

You could use a 5w-20 ..but the OCI would be two weeks or the power output would need to be detuned to allow longer drains

That is, there's no inherent "wisdom" to either school of thought. They're more in the form of preferred exchanges yielding desired results.

 

[SpitfireS]

Originally Posted By: Gary Allan
(and a few other hoops that the Euro's pull out of their behinds on a routine basis)

With "the Euro's" you mean the European car manufacturers... right?

 

[Gary Allan]

Yes. Very leading edge. Not only must it require a 40 grade synthetic ..it must last 10years in service ..while doing the moon walk and a triple gainer off of a rocky cliff in the Alps. (fuel economy, volatility, deposit, wear).

The requirements are kinda an inverted sequestering/channeling of commerce. For example, if not for the fine/narrow channel that the spec's create, there are plenty of synthetic oils to suit the service. It's when you add the "yeah, but does it come in yellow?" specialization that you leave existing formulations in the dust. It's a competition that eliminates much of it.

I guess, without proper context, that could be viewed as "all Europeans"

I'm not really curious about their private distractions

 

[mechtech2]

The oil mfrs. DO show the temp / thickness ratings.
That is what the ratings on the bottle are.

 

[fdcg27]

I have heard the argument before that the oil that the manufacturer used for EPA emissions testing, from which the fuel economy figures are derived, must be the recommended service weight.
Apparently, Subaru didn't get the memo.
For our Subie, a 5w30 SM FE oil is said to be "prefered" in the owner's manual. Subaru then goes on to present a temp/viscosity chart for a range of viscosities and then has text stating that a straight 30 or 40, or 20W-50, including SLs may be used in extreme conditions.
My personal opinion is that most manufacturers use the KISS principle in their oil requirements. We all know that the mechanically ignorant should not be asked to choose the right oil for expected local conditions.

 

[Gary Allan]

Subie surely got the memo ..and for all we know (I'm sure we could find out) ..they may have CAFE credits to burn. Ford took on this MAJOR revolution to allow them to produce more units.

 

[jpr]

So is there something about the subie engine that makes it so particularly sensitive to viscosity differences or are they just playing the CYA game for generic conventional oils?

In BMW's tech lit, they have a similar chart which explains -
Quote:
ACEA specification:
The most suitable viscosity grade should be selected using the viscosity/temperature diagram. Here again, making the right choice will avoid the need for purely seasonal oil changes (e.g. SAE 15w40 for Central Europe). The temperature limits shown in the diagram may be exceeded for a short time. If the upper temperature limit is exceeded, high engine speeds and loads over a prolonged period should be avoided. If the lower temperature limit is exceeded, difficulties may be experienced in starting a cold engine.
This basically amounts to a suggested practice of using a 15w40 in summer and and 5w30 in winter in a whole lot of the temperate world.

For BMW's approved oils however, the following applies -
Quote:
BMW longlife oils, as specified for all BMW vehicles since 1998, are tested by BMW to ensure that they can be used anywhere in the world, at any time of year, regardless of ambient temperature. If BMW longlife oils are used, it is therefore not necessary to keep a check on the viscosity grade.

The mistake some would seem to make is to apply the guidance for low grade conventional oils to modern high performing synthetics. So to answer my own opening question, Subie is playing a CYA game in response to the vast quality range of available oils in the world. BMW took a different approach and developed a short list of high quality oils that they've tested and approved for use.

BMW spec reference can be found here - http://www.opieoils.co.uk/pdfs/BMW-Oil-Specs-and-Recs.pdf