User:Oil lube and fuel

Which Oil to Use

Detergent Oil Virtually all modern multi-weight oils are detergent oils. Detergent oil, cleans the soot of the internal engine parts and suspends the soot particles in the oil. The particles are too small to be trapped by the oil filter and stay in the oil until you change it. These particles are what makes the oil turn darker. These tiny particles do not harm your engine. When the oil becomes saturated with soot particles and is unable to suspend any more, the particles remain on the engine parts. The current oil change intervals the oil is changed long before the oil is saturated. Non-detergent oil, such as SAE 30, is not used in modern passenger vehicle engines. It is still used in some gasoline engines such as lawnmowers.

Oil Viscosity The viscosity of multi-weight motor oil is specified using two numbers. The first number is the viscosity when the oil is cold. This is followed by the letter W (which stands for winter, not weight), which is followed by the number that indicates the viscosity when the oil is at operating temperature. The higher the number the thicker the oil.

Viscosity Modifiers In order to protect an engine at start time, the oil needs to be thinner when cold so it flows freely. Viscosity modifiers are added to the base stock to make the oil flow better when cold, without making the oil too thin when hot. Climate Considerations 10W30 is usually an acceptable alternative to the preferred 5W30 and may be used without measurable adverse effects. In the olden days, before multi-weight oils, it was common to have a winter oil and a summer oil. This is no longer necessary, but if you normally use 10W30 because you live in a warm climate then be sure to switch to 5W30 if you plan on using the vehicle in very cold weather. 5W30 versus 10W30 most all new passenger vehicles sold in the U.S. use either 5W30 or 10W30 oil.

The difference between the two is that the 5W30 flows better when cold, so if you live in a cold climate or operate your vehicle in a cold climate during the winter months, you should use 5W30 if it is the preferred oil for your vehicle. If you live in a sub-tropical climate and don't operate your vehicle in cold climates, then 10W30 is acceptable as long as the manufacturer specifies that it is permissible to use it. Oil lube and fuel (talk) 21:52, 31 May 2008 (UTC) by klozwarehouse