Fundamental understanding about car oil

[aurimask]

Hello,

As i read in theory, it is said, that 0w40 is thinner than 10w30 at startup temperature, even though it is not thin enough (not 10cst)

Now i have a recommendation from blackstone, that i should try to look for 10w30, because they found, that in PRACTICE 10w30 is THINNER oil than 0W40 in startup temperature!

I understand that 0w40 is based on 40w oil and 10w30 on 30w, maybe thats why, but still could someone explain it to me???

 

[addyguy]

At what temperature?

0W-40 wuill be thinner at extreme temps - -35C, where it is tested.

Above that, a 10w30 may well be thinner, b/c it is a thinner oil overall.

If you plot the values on a graph, like the Widamn calculator, you will see where they 'cross' - that is where the 10w30 is thinner than a 0W-40.

 

[sangyup81]

the 0w and 5w have nothing to do with viscocity

both are pumpability ratings

 

[sangyup81]

Here's another thing to throw you off

Pennzoil Platinum Euro 5w40 is 74.4 at 40c
Mobil1 0w40 is 78.3 cSt at 40c

these are the lowest 40c viscosity 5w40 and 0w40 I know of

the thickest 40c viscosity 10w30 I know of is M1 HM 10w30 which is 78cSt

 

[A_Harman]

Originally Posted By: sangyup81
the 0w and 5w have nothing to do with viscocity

both are pumpability ratings


This is not true. The w-number at the front of the viscosity grade is directly related to viscosity, only at low temperatures. Here are the numbers that are used to test for the various w-ratings out of the SAE J300 spec:

Cold Cranking Simulator, Pumpability
0w = 6200 cP max. @ -35C, 60000 cP max @ -40C
5w = 6600 cP max. @ -30C, 60000 cP max @ -35C
10w = 7000 cP max. @ -25C, 60000 cP max @ -30C
15w = 7000 cP max. @ -20C, 60000 cP max @ -25C
20w = 9500 cP max. @ -15C, 60000 cP max @ -20C
25w = 13000 cP max. @ -10C, 60000 cP max @ -15C

So the low temperature ratings are directly dependent on the oil having low enough viscosity at low temperatures.

Viscosity at 40C has nothing to do with the w-number.

 

[ARCOgraphite]

Recall that 40C = 104 F. Thats a pretty hot "cold" start. Starting in anything above "freezer locker" temps, to compare (without getting a headach) the oil with the lowest 100cSt viscosity and the highest numerical VI will be the least viscous (read "thinner') at dead cold "startup"

 

[raytseng]

I think addyguy's got it. depends if your typical cold starts are at like 70degrees versus -30degrees.

That being said, it seems to me that if they're recommending 10w30 because you need a thinner oil at startup temps, it seems to indicate that what they're really saying is your oil at operating temp (40) is also too thick and it's the 30 that they want you to switch to.

Because if you really were to start on the curve in freezing temp, you're going to crossover, pass through the same room temperature point, and then it's just going to get thicker (compared to the 30 oil) from there up to operating temp.

Just split the difference and go with 5w30?,
Or 0w30 but this may cost you a little bit more.

 

[keeganhmorgan]

Originally Posted By: sangyup81
the 0w and 5w have nothing to do with viscocity

both are pumpability ratings


Not true it is the viscosity of the oil at start up, and no matter what temperature the start up is at a 0w oil will lubricate better than a 5w or 10w oil at start up although it will still properly lubricate until the car is warmed up.

But why don't you just go with 0w30 as stated above? It will protect you better during your start up and I think what they were talking about is that you should move to a 30 weight oil rather than a 40 weight oil so that it will lubricate better at normal operating temperatures.

 

[Doug Hillary]

Hi,
keeganhmorgan - You said this regarding ?W ratings:

"Not true it is the viscosity of the oil at start up, and no matter what temperature the start up is at a 0w oil will lubricate better than a 5w or 10w oil at start up although it will still properly lubricate until the car is warmed up."

There are some "conflicting" comments in your statement!

Firstly the 0W to 25W J300 SAE ratings use cP as a unit of measurement. However a cSt rating minimum at 100C is required for each. So whilst it is technically a measurement of viscosity its use is typically confined to from -5C (cranking) to -40C (pumping)

Secondly, please provide evidence that in your words "...and no matter what temperature the start up is at a 0w oil will lubricate better than a 5w or 10w oil at start up..."

Thanks

 

[keeganhmorgan]

Originally Posted By: Doug Hillary
Hi,
keeganhmorgan - You said this regarding ?W ratings:

"Not true it is the viscosity of the oil at start up, and no matter what temperature the start up is at a 0w oil will lubricate better than a 5w or 10w oil at start up although it will still properly lubricate until the car is warmed up."

There are some "conflicting" comments in your statement!

Firstly the 0W to 25W J300 SAE ratings use cP as a unit of measurement. However a cSt rating minimum at 100C is required for each. So whilst it is technically a measurement of viscosity its use is typically confined to from -5C (cranking) to -40C (pumping)

Secondly, please provide evidence that in your words "...and no matter what temperature the start up is at a 0w oil will lubricate better than a 5w or 10w oil at start up..."

Thanks


Here you go BITOG

 

[Doug Hillary]

Hi,
keeganhmorgan - Sorry the Link contains theory but no evidence!

Please oblige.................

 

[keeganhmorgan]

Quote:
Oil type... Thickness at 75 F...Thickness at 212 F

Straight 30...... 250......................10
10W-30............100......................10
0W-30..............40 ......................10

Straight 10........30....................... 6


Find evidence that this is not true then...

 

[Doug Hillary]

Hi,
keeganhmorgan - You made the statement in here and as a new player on BITOG it is perhaps up to you to educate us especially as the title of this Thread is "Fundamental understanding about car oil" - you said this:

"...and no matter what temperature the start up is at a 0w oil will lubricate better than a 5w or 10w oil at start up..."

The Haas chart you have supplied does NOT show any "evidence" that a 0W lubricant will "lubricate better" than a 5W or 10W oil "no matter what the start up temperature is"!

 

[keeganhmorgan]

Originally Posted By: Doug Hillary
Hi,
keeganhmorgan - You made the statement in here and as a new player on BITOG it is perhaps up to you to educate us especially as the title of this Thread is "Fundamental understanding about car oil" - you said this:

"...and no matter what temperature the start up is at a 0w oil will lubricate better than a 5w or 10w oil at start up..."

The Haas chart you have supplied does NOT show any "evidence" that a 0W lubricant will "lubricate better" than a 5W or 10W oil "no matter what the start up temperature is"!



Well it does show that it lubricates better at 75 degrees, and it was made to lubricate better at lower temperatures so I can say it lubricates better at start up temperatures from -30 or whatever temperature it is good to up to 75 degrees. But I believe it lubricates better at any temperature and you have no evidence that it does not.

 

[Doug Hillary]

Hi,
keeganhmorgan - This is a complex issue and the correct message is not delivered well in a statement such as yours. Once above around 0C-15C ambient the "W" rating matters little in the scheme of things - much depends on the lubricant's temperature - as for "lubricate better" it all depends on the formulation of the lubricant - as a complete package!

Offering Mr Haas' comments as "the last word" on automotive lubricants and lubrication is unwise - they are simply the theoretical writings of a very interesting BITOG contributor. IMO they are not however "the Gospel" on lubricants and lubrication

 

[keeganhmorgan]

Originally Posted By: Doug Hillary
Hi,
keeganhmorgan - This is a complex issue and the correct message is not delivered well in a statement such as yours. Once above around 0C-15C ambient the "W" rating matters little in the scheme of things - much depends on the lubricant's temperature - as for "lubricate better" it all depends on the formulation of the lubricant - as a complete package!

Offering Mr Haas' comments as "the last word" on automotive lubricants and lubrication is unwise - they are simply the theoretical writings of a very interesting BITOG contributor. IMO they are not however "the Gospel" on lubricants and lubrication


This is very interesting, do you have any proof that the W rating is not important after it gets above 15 Degrees Celsius? I never said they were "the Gospel" or the bible on lubricants but I have no reason to believe you more than I believe him.

 

[Doug Hillary]

Hi,
keeganmorgan - Please read my earlier Post and consult the SAE's J300 Chart

This is "Fundamental understanding about car oil"

Believe who you shall! I deal in facts and practical reality

You surely joined BITOG to learn and absorb knowledge - so did I

 

[keeganhmorgan]

Originally Posted By: Doug Hillary
Firstly the 0W to 25W J300 SAE ratings use cP as a unit of measurement. However a cSt rating minimum at 100C is required for each. So whilst it is technically a measurement of viscosity its use is typically confined to from -5C (cranking) to -40C (pumping)


I am guessing this is what you are referring to. Could you please explain this better as it does not make sense to me? I did join to learn but that does not mean that I am going to believe everything someone says, just like you did not believe me without proof and neither will I. But I do not know all the technical terms yet.

 

[Doug Hillary]

Hi,
keeganhmorgan - That is why I "challenged" you in the first place. This is a great place to learn about lubricants and lubrication and there are many very knowledgable persons here

One of your first "tasks" may be to learn about the units of "measurement" used in the SAE J300 Chart - cP and cSt. The ability of a lubricant to operate at low temperatures is also shown on the J300 chart

The ability of a lubricant to function properly at a "normal" operating temperature - say >95C has little to do with its "W" rating although an influence may prevail!

CATERHAM'S comments on HTHS viscosity are also worth following - again this is measured in cP not cSt

 

[keeganhmorgan]

Originally Posted By: Doug Hillary
Hi,
keeganhmorgan - That is why I "challenged" you in the first place. This is a great place to learn about lubricants and lubrication and there are many very knowledgable persons here

One of your first "tasks" may be to learn about the units of "measurement" used in the SAE J300 Chart - cP and cSt. The ability of a lubricant to operate at low temperatures is also shown on the J300 chart

The ability of a lubricant to function properly at a "normal" operating temperature - say >95C has little to do with its "W" rating although an influence may prevail!

CATERHAM'S comments on HTHS viscosity are also worth following - again this is measured in cP not cSt



Well I will do my best to learn these things. Can you point out any threads that you think are very good any may help me learn some more about oils?

Are saying that there is a little difference between 0w30, 5w30, and 10w30 at 15 Degrees Celsius but not very much of a difference? And is there a reason that 5w would be better than 0w? As we know at low temperatures a 0w will out perform a 5w but is there any reason a 5w would out perform a 0w?

Edit: I just re-read "The ability of a lubricant to function properly at a "normal" operating temperature - say >95C has little to do with its "W" rating although an influence may prevail!" if there influence at 95C then there must be an influence at 15C so a 0w should still perform better than a 5w at 15C