10w-30, 5w-30 or 10w-40

[2DaTrakNow]

Which weight of oil should be used in our cars? I use either Mobil 1 synthetic, or Castrol Syntec, but every time i go to buy my oil i never remember what should be used. 10w-40 is what ive been using. Also, i know this might sound stupid, but exactly do the numbers stand for? I realize that 5w-30 is "thinner" than 10w-30, but how do the oil companies come up with the 5's, 10's, 30's and 40's?

 

[andymoraitis]

I'm not in the oil business and not all that bright in general so I can't tell you the specific meanings of 5, 10, 15 and 20 (other than what you already mentioned), but I can tell you that 10W-30 is fine for your motor. For higher compression setups that make more heat, thicker oils work better. I run 20W-50 conventional and will switch to 15W-50 synthetic when break in is finished.

Hope that helps,

Andy

 

[ilikespeeding]

The first number is the flow rating when the oil is cold and the second number is the flow rating when the oil is hot.

I like 15W-40 because I live in NC and we dont get that cold of weather, plus the higher weight will protect parts better. You'll scarifice a little gas milage tho.

 

[2DaTrakNow]

so the higher numbers flow less, and are "thicker". So if i live in a warm place, i would pay more attention to the higher number. Then once it starts getting cold out, i should look for a lower first number? Also, since i ran 10w-40 in it last time, i could probably go ahead and run it again right?

 

[eldiabloz13]

The numbers usually refer to weight. 40 weight 50 weight. Now in colder weather you want a lower first number. If you have a high first number it will take sooo long to warm up and will stick to the bottom of your oil pan till kingdom come. Now a higher first number like 15-30 or 10-30 is usually what normal weather people usually would use for summer. hope this helped

 

[v2ner]

Of course you can run it again. BTW...10W40 is the way to go.

 

[2DaTrakNow]

So hang on...i think i understand, but i am going to double check, so please be patient with me! Some of these i know, and some i am trying to find out. Will somebody tell me what is true and what is false.

-The numbers refere to the weight of the oil.
-The first number is the weight of the oil when it is cold.
-The second number is the weight of the oil when it is hot.
-The higher the number, the thicker the oil is and the slower it will flow.
-For example, 10w-40 has a 10 weight when it is cold, and a 40 weight when it is warm.
-5w-40 is thinner than 10w-40 when it is cold.
-10w-40 is thinner than 10w-50 when it is warm.

 

[MadTripper]

Here ya go!

What does the weight mean on a can of motor oil?

Tripper

 

[brodiedehass]

First off viscosity is the internal friction or resistance to flow of a liquid. An oil of low viscosity will flow easily than an oil of high viscosity. Viscosity is measured by how much of a liquid can flow through a given orifice at a given rate compared to water.
There are single-viscosity and multi-viscosity oils. Single-viscosity (ex. SAE 30) oils are used in areas where the temperature is consistent. Multi-viscosity oils (ex. 10W-30) are used in areas where there are seasonal changes or extreme temperature differences between morning and evening. A low numerical viscosity is needed in cold weather, or the engine will have difficulty turning over due to the resistance of the thick oil. A high numerical viscosity oil is needed in hot weather, or the oil will thin out and will not provide enough protection for the engine components.
In oil grades, a "W" stands for winter grade and means that the viscosity test was preformed at temperature of zero degrees Fahrenheit. The "W" in a 10W-30 oil, for example, means that a viscosity of 10 was obtained when the oil was tested at zero degrees Fahrenheit. The absence of the "W" after the 30 designates that a viscosity of 40 was obtained at 210 degrees Fahrenheit.

EDIT: MadTripper beat me to it buy a link, and I spent all that time typing that. Oh well

 

[DGajre777]

I use 10w40.

 

[ilikespeeding]

So, everyone pretty much said the same thing. IMO, here the most important part of the oil rating is the top end. Since you live in michigan, Id use 0W-40 or 5W-40 at the very most.

 

[2DaTrakNow]

So, everyone pretty much said the same thing. IMO, here the most important part of the oil rating is the top end. Since you live in michigan, Id use 0W-40 or 5W-40 at the very most.

i really wont drive my car in the winter though. Some mornings through-out the summer it gets somewhat chilly, but not "freezing" or anything like that. But i will consider at least he 5W-40 just incase!

 

[ilikespeeding]

i really wont drive my car in the winter though. Some mornings through-out the summer it gets somewhat chilly, but not "freezing" or anything like that. But i will consider at least he 5W-40 just incase!

My dad lives in Michigan. He has a 7 liter F250 Desiel that is pretty unforgiving when it comes to lubrication. He is forced to use a block heater, which utilizes two power plugs.

 

[BoBbOrAzE]

I live in Illinois, and for example, I as well as many others use 5w 30 in the winter and 10w 30 in the summer.

 

[2DaTrakNow]

well i went to autozone to pick up my oil, and ive already tried mobil one, and castrol syntec synthetic oils, and i wanted to try to quaker state Q stuff. Well they only had 10w-40 in the "high RPM" oil. I just wanted the "advanced performance" kind, and they only had 5w-30. It seems to be really thin (looking through the clear bottle slightly shaking it), but would anybody recomend this oil? I have never really heard too much about it on this website, just commercials! So the weight of oil i got should be good(or would 5w-30 be too thin?), and what about the brand and type?

 

[sadsm]

Check out this

http://www.carbibles.com/engineoil_bible.html