What is the difference between weights of motor oil?

Answer 1

Viscosity? Viscosity is a measure of the rate of flow of the base oil at a specified temperature. The higher the number , 20w, 30w, 40w the “thicker” more viscous it is. The API sets the specification for the entire industry.

One can vary the viscosity of oil making it behave like 10w at low temperatures (starting) and 30w at normal operating temperatures. (This example would be labled 10W30.) It's done with an additive package that contains molecules which “string together” as the oil warms up.

Multi-viscosity oils are probably better than years ago with the additive package lasting longer. But as the miles pile up, the viscosity range diminishes and eventually it’s a straight weight. 10W30 is probably the best all around; 10W40 if it’s really hot. But the more you try to stretch the viscosity the more problematic it becomes. 5W30 or 5W40 are used by OEMs for certification because they think they get better mileage during start up.

Answer 2

here goes. the higher the number the better viscosity the oil provides.i.e.20w50 is about the highest viscosity oil made. whre as 5w30 is about the lowest.if you are asking which to use it depends on a lot of factors.like some small cars and most newer ones recommend 5w30.if the temperature(outside weather wise where you live)is cold you usually go with 10w30.the bottom number (i.e. the ten in 10w30)represents the oils weight at startup. where as the 30 represents the weight at operating temperature(once your motor warms up). cars tell you in the owners manual which oil is recommended. as i say though most recommend 5w30 if it is newer or a smaller car.the reason being is that the 5 would make it easier on you oil pump to work in the cold weather than say 20 would in 20w50.so if it is cold where you live (really cold use 5w30).there are charts in most owners manuals that tell you the temperature range at which t o use what weight oil.if youlive where it is hot and your car is older you could get away with 20w50. i used that in an older car in the warmer weather (summer in ny).but to use the heavier oil you must have a really good working oil pump.5w30 usually does the job. if you don't have an owners manual for your car check someone elses as a reference for the temperature charts.sometimes it tells you on the front (front clip under the hood by the radiator shroud)what oil to use. it also is located sometimes on your oil cap .

Answer 3

Viscosity - resistance to flowing. Just as honey is more viscous than water, there is a range of viscosities in motor oils. As motor oil cools it gets more viscous so you might want a less viscous oil in winter than in summer. If it's too viscous it will create a drag on the motor. If it's not viscous enough it will not provide sufficient protection from friction, heat build up, etc.

Answer 4

The "weight" is the viscosity or thickness of the oil to pour. The higher the number, the thicker. When it is given as a range, such as 5W-30, it is a multiple viscosity oil. It won't behave thicker than 30 in the cold, or runnier than 5 when at operating temperature.

Answer 5

10W30 or so is for Summer and Winter

In a really old car,in Summer, to reduce leaking, get the 50 instead, like in a 1975 VW or something

higher numbers are thicker

Answer 6

its in the viscosity of the oil,,and what it will remain at once it gets warm,,or hot,,that's where the difference is ,,good luck hope this help,s.

Answer 7

viscosity of the oil