Motor oil weights are published with two numbers separated by a dash. The first number is always followed by a W to represent winter. At lower temperatures, motor oil must resist thickening otherwise it will not be able to flow properly to coat all the moving parts. For example, thick oil will make it harder to start your engine at 0 degrees Fahrenheit. The lower the first number, the thinner oil it is at lower temperatures. [2] Thus, if the number is 5, then its viscosity is better designed to handle cold weather then one with a 10 rating. For winter driving, many cars use 5W-20 or 5W-30 motor oil.
The second number defines oils viscosity at temperatures of 212 degrees Fahrenheit, which is the boiling point for water. The higher the second number, the thicker the motor oil is, which is ideal for summer driving. Most summer oils are rated at 40 or 50 and sold as 10W-40 or 20W-50.
ฉะนั้น ศูนย์ใช้ 10W-40. ก็เป็นsummer oil เหมาะกับประเทศไทยแล้วครับ
