Not sure who this is in regards to but as your post says "5w40 is not thinner oil than 15w40" IT IS IN FACT THINNER under cold start conditions which makes a HUGE difference for ease of starting, and offers better lubrication and protection when cold, once up to operating temp it acts like a 40 weight oil, (not 40 viscosity as you stated).

You are also mistaken as to the "W" designation, it DOES NOT stand for "winter" rating, as so many people still make this mistake. I would suggest you take your own advice and read up on oils, to see what the actual "W" designation stands for, before you post about something that is incorrect.

 

Ok now I'm not sure what you think "w" means........but I can't find anything that disputes it being the SAE designation for a winter or cold temperature flowability..............


The weights given on oils are arbitrary numbers assigned by the S.A.E. (Society of Automotive Engineers). These numbers correspond to "real" viscosity, as measured by several accepted techniques. These measurements are taken at specific temperatures. Oils that fall into a certain range are designated 5, 10, 20, 30, 40, 50 by the S.A.E. The W means the oil meets specifications for viscosity at various low temperatures depending on weight, and is therefore suitable for Winter use. 5W is tested at -25C, 10W at -20C, 15W at -15C, and 20W at -10C.
http://auto.howstuffworks.com/framed...nfo/oiled.html



FAQ #27
27. What does the "W" in 10W/30 stand for?

“W” refers to winter. Oils designated with multiple numbers are referred to as multi-grade oils. These oils will run thinner at low temperatures, the first number, to increase their pumpability. At elevated temperatures, the oil will assume a thicker viscosity represented by the second number. Multi-grades are necessary in low temperature climates.
http://www.hascooil.com/faq/


5W-30 or 10W-30 is better in colder climes. By the way, the 'W' does not stand for 'weight', as many erroneously assume. In fact, the 'W' that is in the S.A.E. designation for an oils viscosity stands for 'winter', indicating that the oil will flow at its rated viscosity in 'winter driving conditions', as defined by the S.A.E.
http://www.boss302.com/oil.htm

 

...........I just can't find anything different............and believe me I'm trying


here are two types of motor oils, single grade and multigrade. Multigrade oils such as a 10W-30, are designed to have the viscosity of an SAE 10W oil at cold temperatures combined with the viscosity of an SAE 30 oil at engine operating temperatures. The "W" or "Winter designation indicates that the oil meets viscosity requirements for low temperatures (below 30°F).
http://www.chevron.ca/ProductsServic...orOilLabel.htm

 

Reread my post. I said, all the oils I listed will "ACT" like a 40 wt oil (about 14.0 - 15.0 cSt @100*C) when up to temp.

You are correct that when in a cold start condition, 5w40 or 0w40 will in fact be "thinner" than 15w40...which is what I pointed out in my first post - the first number is the viscosity index when cold, the second is when up to temp, and the "W" stands for winter. All 100% correct. I guess I didn't write the post for the nitpickers out there - I wrote it to help the original poster in response to his question.

However, if you want to accuse me of posting incorrect info...

From Valvoline's website:
" SAE 40 is SAE 40 no matter what the "W" prefix number is: 5W, 10W, 15W or 20W. The viscosity @ 100 degrees C is within the minim of 12.5 cSt and a maximum of 16.3 cSt." Which is exactly what I said.

Not quite sure why you want to make an issue out of this, but you are wrong on the "W" thing, Demon has proved that. And maybe you'd like to read this from Valvoline's website:
"Most people are familiar with oil's viscosity rating—10W40, for example. However, very few may know that the "W" refers to "winter," not "weight." And most of us have no idea what the weight-rating numbers actually mean other than that the vehicle's manufacturer specifies a particular viscosity"

Nothing I posted was incorrect. You however....

Next time, get YOUR stuff together before trying to roast someone with pure fertilizer...

 

Sorry Man! You and 'ib516' are both correct.
40 wt IS a viscosity of 40 on SAE's system. They are the same thing. (12.5-16.3 cst's at 100* C.)

ib516 - Sorry but I believe Valvoline is not totally correct. I was taught the 'W' does not stand for anything. It is simply SAE's code for 'cold weather cranking'. Roughly it's the viscosity of an oil at -15*F to -20*F... depending on the # in front of it.
But 'Winter' makes it easy to remember and works for me

RJ

 

OK guys to clarify what I posted, as I mentioned there is still lots of confusion about what the "W" actually stands for even from some oil industry people and even some websites, as this post from WIKIPEDIA will clarify. There are 2 different gradings of oil. A single grade like straight 30W oil, and also a multigrade oil like 10w30.

It used to be classified as a "W" meaning winter rating for single grade oil ONLY, but NOT for a multigrade oil. When they introduced multigrade oils, this "W" designation was clarified as a "WEIGHT RATING" for multigrade oils ONLY because of the mixing of the different grades of oil protection range.


The "W" STILL ONLY stands for winter IN A SINGLE GRADE OIL ONLY, in a multi grade oil the "W" STANDS FOR "WEIGHT" not winter. I told you it fools a lot of people still, AND I stand by my previous post for all who didn't like my answer, maybe I should have stated it then, but it was getting late.




AS QUOTED FROM WIKIPEDIA(ENCYCLOPEDIA)

The Society of Automotive Engineers, usually abbreviated as SAE, has established a numerical code system for grading motor oils according to their kinematic viscosity. For single-grade oils, the kinematic viscosity is measured at a reference temperature of 100 °C (212 °F) in units of mm²/s or the equivalent older non-SI units, centistokes (abbreviated cSt). Based on the range of viscosity the oil falls in at that temperature, the oil is graded as an SAE number 0, 5, 10, 20, 30, 40, 50, 60 or 70. The higher the viscosity, the higher the SAE grade number is. These numbers are often referred to as the weight of a motor oil. The reference temperature is meant to approximate the operating temperature to which motor oil is exposed in an engine.

The viscosity of single-grade oil derived from petroleum unimproved with additives changes considerably with temperature. As the temperature increases, the viscosity of the oil decreases logarithmically in a relatively predictable manner. On single-grade oils, viscosity testing can be done at cold winter (W) temperature (as well as checking minimum viscosity at 100 °C or 212 °F) to grade an oil as SAE number 0W, 5W, 10W, 15W, 20W, or 25W. A single-grade oil graded at the hot temperature is expected to test into the corresponding grade at the winter temperature; i.e. a 10 grade oil should correspond to a 10W oil. For some applications, such as when the temperature ranges in use are not very wide, single-grade motor oil is satisfactory; for example, lawn mower engines.


[edit] Multi-grade motor oil
The temperature range the oil is exposed to in most vehicles can be wide, ranging from cold ambient temperatures in the winter before the vehicle is started up to hot operating temperatures when the vehicle is fully warmed up in hot summer weather. The difference in viscosities for any single-grade oil is too large between the extremes of temperature. To bring the difference in viscosities closer together, special polymer additives called viscosity index improvers are added to the oil. These additives make the oil a multi-grade motor oil. The viscosity of a multi-grade oil still varies logarithmically with temperature, but the slope representing the change is lessened. This slope representing the change with temperature depends on the nature and amount of the additives to the base oil.

The API/SAE designation for multi-grade oils includes two grade numbers; for example, 10W-30 designates a common multi-grade oil. The first number associated with the W is not rated at any single temperature. The "10W" means that this oil can be pumped by your engine as cold as a single-grade 10 weight oil can be pumped. "5W" can be pumped at a lower temperature than "10W". "0W" can be pumped at a lower temperature than "5W", and thins less at temperatures above 99°C (210°F). The second number, 30, means that the viscosity of this multi-grade oil at 100°C (212°F) operating temperature corresponds to the viscosity of a single-grade 30 oil at same temperature. The governing SAE standard is called SAE J300. The motor oil grade and viscosity to be used in a given vehicle is specified by the manufacturer of the vehicle.

Some new vehicles are marked to use 0W25 oil. Some ultra fuel efficient and hybrid vehicles are marked to use 0W20 oil

 

As posted by ib516-QUOTE

Nothing I posted was incorrect. You however....

Next time, get YOUR stuff together before trying to roast someone with pure fertilizer...
_
_________________



I DO have my stuff together very well thank you, YOU DID NOT before you replied , but now you do. You are VERY welcome

 

Originally posted by DEMON-Quote-


Ok now I'm not sure what you think "w" means........but I can't find anything that disputes it being the SAE designation for a winter or cold temperature flowability..............


The weights given on oils are arbitrary numbers assigned by the S.A.E. (Society of Automotive Engineers). These numbers correspond to "real" viscosity, as measured by several accepted techniques. These measurements are taken at specific temperatures. Oils that fall into a certain range are designated 5, 10, 20, 30, 40, 50 by the S.A.E.


" The W means the oil meets specifications for viscosity at various low temperatures depending on weight, and is therefore suitable for Winter use"
-Quote-








Demon, you had your answer on last paragraph from your post above. As you can see the "W" reference is to the "WEIGHT" of oil, and not "WINTER" it only says it is therefore suitable for winter use. It makes NO reference to the "W" standing for WINTER.

 

Not to stir this fire too much (because I'm loosing interest) but For Torque.... I found at least 3 errors in the statements made by your encyclopedia. Just to verify I caught our Chemist as he walked by and asked him to read it also.... and he agreed.

I'm out of here!

RJ

 

And what would those supposed errors be specifically RJohnson, you can't be losing too much interest if you posted this reply, aren't you going to explain yourself?

I was taught it meant "weight" in Lubrication courses I took, and very similiar to what I posted from Wikipedia. You will find it in many prominent postings/books you find from reputable sources. The problem is anyone can get the wrong information, and say it is right.

You said the "W" meant nothing, well you are wrong , so if you have some info from a reputable source then post it for all to see, not just empty words or just your opinion, as I welcome a discussion.

 

Another good ol oil thread
I thought everything was way too civil for an oil thread on the first dozen or so posts Seriosuly though even oil threads are pretty civil here in dtr

 

"ORIGINALLY QUOTED BY TORQUE"And what would those supposed errors be specifically RJohnson, you can't be losing too much interest if you posted this reply, aren't you going to explain yourself?

I was taught it meant "weight" in Lubrication courses I took, and very similiar to what I posted from Wikipedia. You will find it in many prominent postings/books you find from reputable sources. The problem is anyone can get the wrong information, and say it is right.

You said the "W" meant nothing, well you are wrong , so if you have some info from a reputable source then post it for all to see, not just empty words or just your opinion, as I welcome a discussion.
__________________




rjohnson, We're all still waiting for you to explain your comments from your previous post, from either you OR your chemist AND NOT JUST YOUR OPINION AGAIN. WE NEED SOME PROOF NOW FROM YOU, TO BACK UP YOUR STATEMENTS. BTW, I've got lots more pertinent information here to keep this thread going for a LONG LONG time.

 

Operating cost is of a major concern to me, for that reason alone, I use
Shell Rotella T and ad a friction modifier.
For kicks @ 250K I pulled a injector and peaked in the cylinder, everything looked good. Service interval is 7/8K and I use the Mobil 1 micro media filter.
Because of the rear seal and breather I add a qt. every 1,500 miles.
I'm guessing here, but I doubt anyone on this forum pulls the weight I'm asked to tug under the conditions and locations I sometimes have to travel.
Synthetic is great and I'm not knocking it (and use it {NEO} in my hot rod).
If I lived in a colder locale, I would consider using synthetic or at least plugging in the block heater when conditions make it necessary.
pc