You are probably one of two types. You either change the oil in your car religiously, or you neglect it until there is nothing left to read on the dipstick or the “oil” light shines on your dashboard. Okay, maybe you fall somewhere between the two. But do you know why motor oil is so important to your engine and the reason you should replace it regularly with a quality product?
Surely a lot of drivers have a vague sense that it is important to change engine oil every so often. Most might identify that it is bad for an engine to run low on oil. Or know that old, dirty oil could be a cause for concern. But why? What does motor oil do for your car? What if you wait too long between oil changes? Or use the wrong kind of oil?
Here is an overview of how motor oil can affect your engine’s performance.
The mission of motor oil
Inside your engine is a symphony of moving metal parts that work in concert to produce power. Pistons move up and down in their cylinders as they respond to bursts of energy during the combustion process. A series of lifters, rockers, and pushrods move with the camshaft to open and close up to three dozen valves to let air and fuel into the cylinders and exhaust out. The pistons pedal a heavy crankshaft that transmits torque to your transmission so your car can move.
If it were not for motor oil, all of those metallic components would be scraping against one another. Motor oil serves as a thin film to lubricate those parts, reduce friction, and prevent too much heat from building up.
You can imagine that motor oil needs to work pretty hard to do its job. And not just any old oil will do. For instance, each engine is designed to operate with a specific grade of motor oil. Grade (or weight) is a way of describing the viscosity of oil. (Viscosity is a liquid’s ability to resist flow – how thick or thin it is). Oil needs to be thick enough to coat those components, but thin enough to flow into all of the nooks and crannies inside your engine.
When it comes to viscosity grades, the higher the number, the thicker the oil. Modern motor oil comes in multi-weight (multi-grade) formulas. You have seen them on store shelves: 10W-30, 5W-20, and the like. Those are products capable of acting like low-viscosity oil when cold (the “W” stands for winter) and high-viscosity oil when warmed up.
See, oil tends to get thinner when it gets hot. Therefore, oil manufacturers include additives that combat that phenomenon. So, 5W-30 oil acts as 5-weight oil when cold to help you get your engine running, and 30-weight oil when your engine warms up.
Motor oil quality also differs from one brand and product to the next. The oil you use in your engine should meet the standards set by the American Petroleum Institute (API) and bear their “Starburst” certification mark and “Donut” service symbol.
When is the right time to change your oil?
With regular use, motor oil will break down over time. Just like with brake pads, oil wears out and, along with the oil filter that removes unwanted debris, needs to be replaced. But how often should you look to change your oil?
Well, the answer is not, “every three months or three thousand miles.” At least not for most drivers. Unless you drive in the harshest of conditions, that old oil change adage from decades ago really does not apply to your engine. Of course, changing your oil so frequently will not cause any harm (other than to your wallet), but most automakers recommend longer intervals, usually 5K miles or more.
So, how do you know when it is time for an oil change? When your vehicle manufacturer tells you to. Routine service information is printed in your owner’s manual. Intervals can range from 5K to 10K miles, sometimes more. Every engine has a recommendation from the manufacturer that you should follow.
You might be able to increase the intervals between oil changes if you switch from conventional oil to synthetic oil. Synthetic oil is a type of product that is engineered artificially in a lab rather than distilled directly from crude oil pumped from the ground. As a result, quality synthetic motor oil (such as industry-leading Mobil 1™ full synthetic oil) is more uniform at a molecular level, is more stable and less prone to thermal breakdown, and contains higher-caliber additives than conventional oil. It protects better and lasts longer. As long as your engine does not already call for synthetic oil – some engines include synthetic oil from the factory – then you might be able to extend the intervals between oil changes.
Check your owner’s manual for the manufacturer’s recommendation for what type of oil you should use, and check with a trusted repair shop about the option to switch to synthetic motor oil in your engine.
What happens if you wait too long
What if you drive too long between oil changes? What if you neglect to have your oil changed on time? Will your engine be destroyed? Maybe. Probably not, at least not right away.
The truth is, if you miss an oil change by a few hundred, or even a thousand miles, you will not likely cause much damage. But over time, old oil breaks down and turns to sludge that clings to engine components, clogs passageways, and fails to find its way into the tight tolerances of a modern motor. The more you put off those oil changes, the more sludge builds up. Besides, harmful dirt, metal particles, and acids that accumulate in your oil can degrade engine parts. The ability of the oil to help cool your engine also diminishes. You might not kill your engine by overshooting the mileage mark for your next oil change, but you could contribute to its demise.
Thermal breakdown and sludge are major contributors to engine failure. So, neglecting oil changes can cause great harm, whereas timely service will prolong the life of your engine. In fact, routine oil and filter changes are the simplest – and most important – actions you can take to get years of life from your car, truck, or SUV.
What if you use the wrong oil
Now, if you happen to find a special on a five-quart bottle of 10W-30 motor oil, do not buy it! Not unless your engine specifically calls for 10W-30. Some auto owners wrongly assume or believe that thicker oil lubricates better than thin oil. Some old engines from a time when engine tolerances were far less precise than they are today benefited from thicker oil that would fill spaces between engine components. But a modern engine has very little space between its pieces and needs low viscosity oil to keep it lubricated properly.
Whereas heavier oils (such as 10W-30) were common decades ago (See “The History of Oil), today you will routinely find designations like 5W-20, 0W-20, and even 0W-16 on the shelf. Those oils are able to provide protection that heavier oils cannot. It all depends on what oil is supposed to be in your engine.
What happens if you use the wrong oil? Motor oil that is too thick will not flow into places where thinner oil will. That means metal-on-metal contact can wear away at engine parts. Oil that is too thin, on the other hand, might not have the sheer resistance necessary for your engine. That could lead again to metal contact, along with reduced oil pressure. In short, using the wrong grade of oil will result in reduced lubrication and shorter engine life. It might even void your warranty.
Motor oil and your engine
The benefits of quality motor oil, like the line of Mobil 1™ synthetic oils, are many. Reduced friction, excellent cold-weather and extreme temperature protection, reduced deposits, smoother startup, and (most conspicuously) improved fuel economy are all made possible through routine oil and filter changes with quality products. Not only will your engine work more effectively. It will also work longer.
Columbia Auto Care & Car Wash | Author: Mike Ales | Copyright December 2019
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