What does the W stand for in motor oil like 5w30...?

Question

any Jiffy lubers out there will know this answer...

Answer 1

It's WINTER. I see so many thumbs down for that answer, yet it is the only correct one.
The weight, or viscosity, is the number part of it... the different numbers are the different "weights" of oil. So that info is already in there.

http://www.bobistheoilguy.com/oildefinitions.html
http://www.chevron.ca/ProductsServices/Retail/MotorOilLabel.htm
http://www.fulltimerver.com/techtips/oil-numbers.html
http://www.njcost.com/_disc14forumtalk/00000016.htm

And finally, this site will tell you more about engine oil than you ever wanted to know...
http://www.chris-longhurst.com/carbibles/engineoil_bible.html

Never ask Jiffy Lubers about oil! lol.

Answer 2

We get asked this question so often that we have included this special page dedicated exclusively to answering the question.

AMSOIL 0W-30, 5W-30 and 10W-30 synthetic motor oils are ALL 30 weight oils. The answer is that ANY one can be used regardless if your vehicle owners manual says to use, for example, a 5W-30. "W" means WINTER. In winter weather the 0W oil will flow like a 0W oil, and the 5W will flow like a 5W oil and a 10W will flow like a 10W oil just until the engine warms up. In order to understand the differences one has to first understand that the numerical values given to these various weight oils are strictly empirical numbers. For example, 0W does not mean that the oil has no weight. That is one of the reasons why we say it is strictly an empirical number.

In order to determine the differences between the three oils one has to look at the kinematic viscosity of each lubricant. The kinematic viscosity is essentially the amount of time, in centistokes, that it takes for a specified volume

of the lubricant to flow through a fixed diameter orifice at a given temperature.
Let's compare the kinematic viscosity of the three AMSOIL lubricants

AMSOIL 0W-30 is 57.3 cST @ 40 °C, & 11.3 cST @ 100 °C

AMSOIL 5W-30 is 59.5 cST @ 40 °C, & 11.7 cST @ 100 °C

AMSOIL 10W-30 is 66.1 cST @ 40 °C, & 11.7 cST @ 100 °C

As you can see from the data above the kinematic viscosities are extremely close. Therefore, whether you use the 0W-30, 5W-30 or the 10W-30 is strictly a matter of choice. With the small differences in kinematic viscosity you would be hard-pressed to detect these differences on initial engine start-up without specialized engine test equipment.

All three oils are excellent motor oils and ANY one can be used in a vehicle which requires either a 0W-30, 5W-30 or 10W-30 oil as well as in several other engine applications including an engine which recommends a 5W- 20 oil.

Answer 3

W In Motor Oil

Answer 4

Winter


From Wikipedia:
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 (again 'W' is for Winter, not Weight) is not rated at any single temperature. The "10W" means that this oil can be pumped by your engine as well as a single-grade SAE 10 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.

Answer 5

Weight

Answer 6

automation wizard is right. it is winter. winter for cold. though 99% of people believe it is weight. the 2 numbers mean how thick or viscous the oil is, 5 (when its warm is fairly thin) and Winter30, means its thicker when its cold

Answer 7

Weight. Refers to the viscosity of the oil. (I am not a Jiffy Luber, by the way...)

Answer 8

.The W in motor oil stands for weight, which is the viscosity of the oil. 5 W 30 means it has the viscosity of 5 weight oil at freezing and 30 weight viscosity at higher temperatures. When oil gets cold it doesn't flow well, so chemist found the solution

Answer 9

Weight. The first number is the weight and the second tells the grade. It basically lets you know how thick the oil is. Some cars require thicker oil, while other cars require not so thick. As a car ages, though, it may be better to use something other than what your owners manual says, so you may want to talk to a TRUSTED mechanic and see what he suggests.

Answer 10

Weight, and the other numbers give temperature range and viscosity (thickness) Since tempature effects how the oil flows high temp 50 weight is thicker than a 20 weight