Engines tend to last longer these days, one reason being that modern oils are so much better. But to get the maximum benefit, you must use the correct oil for your engine. You need to know two things about oil - its viscosity and its API rating.
Viscosity
This is a measure of the oil's thickness. As it heats up, oil gets thinner or runnier. Modern oils have additives to help stop them getting too thin when hot. The viscosity rating has two numbers, one for when the oil's cold, and the other for when it's hot (the bigger the numbers, the thicker the oil). 15W-40 oil behaves like a 15-grade mineral oil when cold and 40-grade oil when hot. Use what the handbook suggests for our climate.
The American Petroleum Institute (API) sets performance standards for oils. For petrol engines, these start with an "S", as in SJ. Diesel engines start with a "C", as in CH-4. These standards are upgraded every few years. You must use at least the rating that was current when your car was made (check the manufacturer's recommendations). For a car a few years old, using later-rated oil could extend engine life. The latest API rating for petrol engines is SM.
Environment watch
Used oil can be burnt as a furnace fuel. Do the environment a favour and take yours to the collection facilities provided by some service stations and local body recycling depots.
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