I read somewhere that the W stands fdor Winter and I don't understand what the winter is in a definition of oil. Then what about the 10 W 40 or the 5 w 20 ?
please adivise.
thanks
2007-05-11 14:29:12 · 3 answers · asked by chris w 1 in Cars & Transportation ➔ Maintenance & Repairs
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. A specific oil will have high viscosity when cold and a low viscosity at the engines operating temperature. 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 idea is to cause the multi-grade oil to have the viscosity of the base number when cold and the viscosity of second number when hot. 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 (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.
2007-05-11 14:33:15 · answer #1 · answered by Stuart 7 · 4⤊ 0⤋
10w30 W stands for weight. The weight of the oil. 30 is the weight of the oil cold before you start the engine. 10 is what the oil goes to when it warms up.
2007-05-11 17:27:27 · answer #2 · answered by papabear 4 · 0⤊ 0⤋
you need light weight oil in winter like 5w30 and 10w40 in summer because oil changes viscosity due to heat
2007-05-11 15:04:54 · answer #3 · answered by Jared H 1 · 0⤊ 0⤋