Oil is NOT thinner when cold.
- Thread starter BlazerLT
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"If "30 weight" is just a "category" then oil companies are free to market 0w30, 5w30, or 10w30 as a straight SAE 30. "
What if the "SAE 30" can meet a 20w test? Is that then a point of contention?
What if the "SAE 30" can meet a 20w test? Is that then a point of contention?
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Come on, we all know numbers are meaningless.
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Yeah! Remember the twinkie!
moribundman wrote: "Come on, we all know numbers are meaningless."
Do you mean grades are meaningless? I tend to find that numbers, once the context is know, is one of the few things whose meaning is undisputed.
Do you mean grades are meaningless? I tend to find that numbers, once the context is know, is one of the few things whose meaning is undisputed.
twinkie here, hamburger helper in another thread, I'm getting hungry..
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GM ..you need to get to know mori a bit better...
I have no desire to get into the middle of this "what is a 30 weight" debate because it is stuck on some obscure points.
But I think G-Man is using the term 30wt to mean SAE 30 straight grade, while the commonly accepted usage is much broader.
The category 30 weight oil includes the following subsets:
0W-30
5W-30
10W-30
SAE 30 straight grade
All these viscosity grades are a 30 weight oil as defined by the original SAE testing proceedure of taking x amount of seconds to flow thru a calibrated orfice at a temp of 100C.
But I think G-Man is using the term 30wt to mean SAE 30 straight grade, while the commonly accepted usage is much broader.
The category 30 weight oil includes the following subsets:
0W-30
5W-30
10W-30
SAE 30 straight grade
All these viscosity grades are a 30 weight oil as defined by the original SAE testing proceedure of taking x amount of seconds to flow thru a calibrated orfice at a temp of 100C.
One big premise in my articles is that we should do away with the current labeling system as it is confusing (see above posts).
The current label is based on viscosity yet the numbers do not represent viscosity. Instead we should put on the label several viscosities assuming that is what should be represented. For example give the viscosity at these temperatures:
- 20 F
50 F
120 F
200 F
300 F
I choose the oils I use only on the viscosity. I do not care what the brand is or if it is synthetic. Personally I think the blends will show the best performance in the routine car than either dino or synthetic alone.
My basic search is to find an oil that has the least viscosity at 75 F. This is my average start up temperature. And then it must have the appropriate viscosity at 200 F. This is, as far as I can tell, my highest operating temperature. If you cared about the viscosity at 300 F (I do not) then an oil as Red Line 5W-20 is least thick at lower temperatures, just right at 200 F and the viscosity at 300 F is enough for just about any engine. This is but one example.
aehaas
The current label is based on viscosity yet the numbers do not represent viscosity. Instead we should put on the label several viscosities assuming that is what should be represented. For example give the viscosity at these temperatures:
- 20 F
50 F
120 F
200 F
300 F
I choose the oils I use only on the viscosity. I do not care what the brand is or if it is synthetic. Personally I think the blends will show the best performance in the routine car than either dino or synthetic alone.
My basic search is to find an oil that has the least viscosity at 75 F. This is my average start up temperature. And then it must have the appropriate viscosity at 200 F. This is, as far as I can tell, my highest operating temperature. If you cared about the viscosity at 300 F (I do not) then an oil as Red Line 5W-20 is least thick at lower temperatures, just right at 200 F and the viscosity at 300 F is enough for just about any engine. This is but one example.
aehaas
I think the biggest thing that people do not understand when it comes to how to read a multi-viscosity oil is that the pre W number and post W number are two entirely different "metrics" if you will. They can't be compared. If both numbers measured kinematic viscosity, the post W number at 100C and lets say, the pre W number at -30C, then a 10w-30 oil would actually read about 5000w-30 (assuming they had a kinematic viscosity grade for an oil that was about 15,000 centistokes)
I know I said my previous post was my last word on the subject, but I want to comment on this.
IF one is using the term "30 weight" to refer to a "category," then I do concede the point. However, I have never used the term "30 weight" as a category, and I don't believe it is "commonly accepted usage" to do so except by those who want to make it a category. "30 weight" is just that: it's a SAE 30 grade oil. It's not a SAE 5w30 or SAE 0w30 or SAE 10w30.
How many people would be happy to find out that the SAE 30 Havoline they have been using turns out to actually be 5w30 Havoline and when they complain to ChevronTexaco the response they get is "Well it's all the same thing since '30 weight' is just a category and 5w30 is a 30wt according to the J300 specs"?
If "30 weight" is just a "category" then oil companies are free to market 0w30, 5w30, or 10w30 as a straight SAE 30.
I only joined the car owning society when 20W50 was in vogue.
Is there any connection to the xxW terminolgy, when a straight 20wt was used in winter and a higher wt in summer. Did a 20wt originally meet the API specification for a 20W, Pre Redline.
Is there any connection to the xxW terminolgy, when a straight 20wt was used in winter and a higher wt in summer. Did a 20wt originally meet the API specification for a 20W, Pre Redline.
whew.... i would sum this thread up as "folks who THINK they know everything are annoying to those of us that DO!"
I will be the first to use an oil that is a 5W-5. That way no matter what I say about its flow or weight, I'll be right.
The naming system is a hold-over from when they were measured on the same metric. There was a kinematic viscoisty range established for SAE 5, 10, and 20 oils measured at 0 degrees F. This was the "Winter" (W) viscosity measurement. A 10W-30 meant exactly that: an oil that met the viscosity specifications for an SAE 10 at 0F and a SAE 30 at 212F.
The advent of the current specifications using "dynamic" measurements, taken at different temperatures and different specifications for each 'W' grade makes the naming system far less descriptive of how the oil really preforms at cold temperatures.
As AEHass says, a new naming system could be implemented for those of us who can, or want to, understand how the oil really behaves.
The current naming system works fine for the 99.999% of peope who read in their owner's manuals that if they use anything but xxW-yy oil the car it will; not be covered under warranty, turn to dust within 5 seconds, cause the Earth to stop spinning, and will send them to an eternity in h-e double toothpicks.
Ed
"oil that met the viscosity specifications for an SAE 10 at 0F and a SAE 30 at 212F"
It's already been pointed out that's a physical impossibility. 10 is thinner than 30. +0f is colder than +212f. All oil is thicker when cold.
It's already been pointed out that's a physical impossibility. 10 is thinner than 30. +0f is colder than +212f. All oil is thicker when cold.
From Synlube site
"here is in brief what has happened over the 70 years.
SAE 60 grade was added as the need for thicker oil in aviation and heavy duty engines became apparent.
SAE "W" grades were added in 1952 as it became apparent that engines could not be started in Cold Winter Climatic conditions with some SAE 30 oils. The "Winter" (W) performance was originally defined as viscosity at 0°F or -11.8°C.
SAE 5W and later SAE 0W grades were added as thinner "economy" oils needed to be defined.
Additional test specifications for winter performance were added to "W" requirements as engines failed mechanically in cold climate immediately after initial start, due to oil starvation.
SAE 15W and SAE 25W grades were added to further narrow the performance definitions in Winter Climates.
In 1970's minimum high temperature high shear specifications were added for performance at 150° C, when it became obvious that engines suffered from excessive wear or even seized at high speed high temperature operation such as long distance interstate driving or towing in Hot Summer climate.
So the changes to SAE J300 Standard were usually, until very recently, a reaction to "fix" an existing problem with lubricants that caused engine problems in service. This was either due to viscosity breakdown when hot or failure to flow when cold. In either case, resulting in catastrophic engine failures.
Last few SAE J300 Standard changes were PROACTIVE. They were legislated jointly by the auto and engine manufacturers, as well as, the lubricating oil producers, before any problems in the field occurred. This was based on research tests in the laboratories, and therefore done in anticipation of problems before they had chance to occur.
Many of these specification changes were necessary because today’s cars equipped with electronic fuel injection and electronic ignition will start immediately at much lower temperatures, than vehicles made just a decade ago.
"here is in brief what has happened over the 70 years.
SAE 60 grade was added as the need for thicker oil in aviation and heavy duty engines became apparent.
SAE "W" grades were added in 1952 as it became apparent that engines could not be started in Cold Winter Climatic conditions with some SAE 30 oils. The "Winter" (W) performance was originally defined as viscosity at 0°F or -11.8°C.
SAE 5W and later SAE 0W grades were added as thinner "economy" oils needed to be defined.
Additional test specifications for winter performance were added to "W" requirements as engines failed mechanically in cold climate immediately after initial start, due to oil starvation.
SAE 15W and SAE 25W grades were added to further narrow the performance definitions in Winter Climates.
In 1970's minimum high temperature high shear specifications were added for performance at 150° C, when it became obvious that engines suffered from excessive wear or even seized at high speed high temperature operation such as long distance interstate driving or towing in Hot Summer climate.
So the changes to SAE J300 Standard were usually, until very recently, a reaction to "fix" an existing problem with lubricants that caused engine problems in service. This was either due to viscosity breakdown when hot or failure to flow when cold. In either case, resulting in catastrophic engine failures.
Last few SAE J300 Standard changes were PROACTIVE. They were legislated jointly by the auto and engine manufacturers, as well as, the lubricating oil producers, before any problems in the field occurred. This was based on research tests in the laboratories, and therefore done in anticipation of problems before they had chance to occur.
Many of these specification changes were necessary because today’s cars equipped with electronic fuel injection and electronic ignition will start immediately at much lower temperatures, than vehicles made just a decade ago.
I think what has to be determined is if the, say OLD 10w "cold" spec represents the same actual visc of a SAE 10 oil (as defined at +100c) hot, which is impossible as that is quite thin. Or if the reference to an SAE 10 as "W"-rating meant the multigrade being the same visc at +0f AS A SAE 10 (as defined at +100c) WOULD BE at +0f, kinda thick... which makes sense, to a point. That point being that the hypothetical SAE 10 (w) oil would have to be a SPECIFIC TYPE of oil. Follow me? Raw crude or Castor Bean oil or Cod Liver oil or whatever...that all likely have different cold visc properties. Make sense?
Makes sense as from same site
oil sourced from Gulf Coast, for example, could be thick when cold, yet unable to protect the engine adequately when hot.
By contrast another oil from Pennsylvania, which was lot easier to pour when ambient, would be just right for automotive engine when hot.
The first example of the thick when cold and really thin when hot, was oil with low viscosity index.
VI of ZERO – The thick black Gulf Coast Aromatic crude would behave like this.
The second example of the not so thick when cold and not as thin when hot, would be the oil with high viscosity index. VI of 100 (then thought to be the BEST possible) – The amber oil which came from the oil fields of Pennsylvania and consisting of the paraffin crude that made Pennzoil and Quaker State world famous.
http://www.synlube.com/sae5w-20.htm
oil sourced from Gulf Coast, for example, could be thick when cold, yet unable to protect the engine adequately when hot.
By contrast another oil from Pennsylvania, which was lot easier to pour when ambient, would be just right for automotive engine when hot.
The first example of the thick when cold and really thin when hot, was oil with low viscosity index.
VI of ZERO – The thick black Gulf Coast Aromatic crude would behave like this.
The second example of the not so thick when cold and not as thin when hot, would be the oil with high viscosity index. VI of 100 (then thought to be the BEST possible) – The amber oil which came from the oil fields of Pennsylvania and consisting of the paraffin crude that made Pennzoil and Quaker State world famous.
http://www.synlube.com/sae5w-20.htm
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