What is the role of motor oil in the engine?

Cars these days have become a lot more reliable and manufacturers have taken away the ability to tinker with your car's engine and other systems. For the most part this has been a good thing, no one want less reliable cars but it also means we are mostly dependent on the manufacturer for servicing and this can make services more expensive. However, all that aside one area that you definitely need to know about is your motor oil. Motor oil does many things inside the engine, these are just some of them:

• prevent wear and tear
• reduces friction there for improving efficiency
• cools by dispersing heat
• cleans and prevents corrosion
• help start the car (especially in cold conditions)
• holds dirt and unwanted detritus in suspension, therefore keeping it away from the engine

Oil also contains additives. These chemicals are added to the oil when it is refined to improve the oil's ability to do its job. Additives include detergents for cleaning, oxidation and rust inhibitors and viscosity improvers to help keep the oil flowing when it's cold. The flow of oil is measured by the mechanical or electric oil pressure gauge and if it is too low the engine can become damaged.

Eventually the motor oil will need changing because the additives get used up over time. The oil also becomes dirty because of the accumulation of contaminants which are either by-products of the combustion process or tiny fragments of metal that have broken away from the engine.

How often you change the oil will depend on your car and the mileage you drive. Your car owners manual will have a recommendation. Changing the oil is a simple process and there are many web sites to help you do it but if you are not confident about DIY car maintenance get a mechanic to do it for you. Make sure you get the right kind of oil. Usually this will be a multigrade. Also, do be fobbed off with a cheap oil change. You need API approved oil that contains the additives your engine needs.