The number one question people ask about motor oil is What kind of oil should I use? or some version of that question. What brand? What type? When it comes to maintaining your car , you probably have at least a general knowledge that you need to change the oil every so often. But maybe you are not so sure about what to put into your engine when it comes time to do so. With so many slick marketing ads for this product or that, each boasting superior protection and extended engine life, it can be difficult to navigate the highly competitive motor oil market.
It is kind of like buying a new set of golf clubs. Forged or cavity back? Game improvement irons or ultra game improvement irons? What brand is the best? Every iron has technology built into it to help you with your swing. Same with motor oil: every product on the shelf has been formulated to do a specific job. So, what oil really is the best one to use? Fortunately, you do not need a firm grasp on physics or chemistry to understand the surprising answer to that question.
The purpose of motor oil
You do not need to be a pro golfer to buy a new set of golf clubs, and you certainly do not have to be a scientist to appreciate what motor oil does for your engine.It does, however, help to know the basics. So here goes.
Motor oil (also called engine oil) is the lubricant in charge of reducing friction inside an engine. In your vehicle’s engine are all sorts of moving metal components: pistons, connecting rods, valves, crankshaft, camshafts, and more. Hundreds of moving parts travelling at high rates of speed. Motor oil creates a thin lubricating film between those parts, separating (for example) a piston from the walls of the cylinder in which it travels up and down thousands of times per minute.
In addition to lubricating your engine’s internal components, motor oil also helps (by reducing friction) to reduce heat. Chemical compounds added to motor oil, known as additives , also serve to do other jobs, like improve viscosity , prevent corrosion, clean engine internal surfaces, and prevent sludge from building up.
But just because a motor oil product does each of these things – certainly every product strives to do so – does not mean it is right for your engine.
The properties of motor oil
In order for motor oil to do its job properly in your engine, it must meet certain criteria, both in terms of quality and suitability. But what makes one oil product better than the next, or more suitable for one engine and not another? This is where a basic understanding of motor oil helps. The quality of a motor oil product makes a difference when it comes to choosing the right oil for your car; so do its weight, type, and rating.
Theweightof a motor oil refers to its viscosity , its resistance to flow. Think about viscosity in terms of how thick or thin it might be. Water is extremely thin and runny, of low viscosity, whereas honey is much thicker and of higher viscosity. Tar is higher yet. Motor oil is available in various degrees of viscosity. Some thicker, some thinner. You have seen indicators of oil viscosity printed on the bottle in terms such as 5W-20 or 0W-16, where the first number represents the oil’s viscosity at low temperatures (“W” stands for winter) and the second number its viscosity at operating temperature. This weight designation is also referred to as its “grade”, so the terms weight, grade, and viscosity are often used interchangeably.
Another consideration when choosing motor oil is its type . Is it conventional oil, synthetic oil, or a semi-synthetic blend? In a nutshell, conventional (some people call it “ regular” oil ) is derived and distilled directly from crude oil pumped from the ground. Synthetic oil , on the other hand, is created artificially in a lab to far more precise specifications than conventional oil and therefore is considered to be of higher quality and possess better characteristics, albeit at a higher price. Semi-synthetic blends are exactly what they sound like: a blend of conventional and synthetic oils to offer some of the protection of synthetic while keeping the price down.
Now, motor oil is evaluated by the API, the American Petroleum Institute. API assigns a rating certifying that a product meets certain Original Equipment Manufacturer (OEM) quality and performance standards, two of which are of concern for you. One of those standards is the oil’s viscosity. Another is the API Service Category that signifies the performance properties of a product.
Armed with the awareness of motor oil’s weight (grade, viscosity), type, and rating, you can choose the oil that is right for your engine. But how? How is that information useful to you if you do not know how it relates to your car?
The plan for motor oil
Pretty much any golfer knows that golf club manufacturers come out with a new design nearly every year. With each new year and new design, those manufacturers make claims that you can get more distance, greater accuracy, and a better feel from their clubs than from the previous model or from the competition. Well, who is right? Titelist? Taylor Made? Cobra? Truth is, while there may be slight differences between this club and that, they are all capable of producing fine golf shots. It may be, however, that one club is better suited to a particular player.
Similarly, motor oil manufacturers play the same marketing game, each trying to outdo the others with their marketing efforts. Certainly there have been advancements made over the years in motor oil technology – you would not use oil from thirty years ago in a modern engine – but all of the major manufacturers have been making improvements, all offer oil of various weights and types, and all must meet API standards.
But that is not to say that every bottle of motor oil is suited for your engine. No, your engine requires a specific weight or grade of oil. It requires a particular API rating. And it may even require a specific type. How do you know? How do you know what oil is right for your car? Or which product is best?
That is where the plan comes into play. Your vehicle’s manufacturer, the OEM, designed your engine to run with oil of a specific weight, type, and rating. Engineers crafted a plan for your oil: how often you should change it and what oil you should use when you do. The plan is not a secret. The OEM hands it to you when you purchase the vehicle. Otherwise, you can usually find it lying in your glove compartment. The specifics related to your oil changes are printed for your reference in the Owner’s Manual for your car, truck, or SUV.
Could it really be that easy? Sure. Your owner’s manual will designate whether you should use 5W-30 or 5W-20 or 0W-16 or some other weight of oil. Use what the manufacturer recommends, because that is what your engine needs. Oil that is too thick will not flow into certain tight areas of your engine; oil that is too thin will not fill others and might not stand up to the shearing forces produced. Stick with the number in your manual!
The owner’s manual will also give you an API rating for motor oil. Vehicles with a gasoline engine will have a two-letter designation that begins with “S”, whereas diesel engine ratings begin with “C”. The second letter essentially identifies various standards over the years, with the oldest for a gasoline engine bearing an “SA” rating (prior to 1930) and the newest an “SP” rating. It is important to note that oil with an improper API rating can be unsuitable for your engine and may be entirely obsolete for most any engine.
The only other factor to consider is the type. Here, you might have some flexibility. Might. Many engines come from the factory with conventional oil installed. When that is the case, you can either choose to replace it with conventional or upgrade to synthetic or a synthetic blend. But as engine technology improves and lighter-weight oils become more common, synthetic oil is being installed in the factory. When that is the case, you need to stick with synthetic oils . In fact, lower viscosity oils are only available synthetically.
Let’s use a 2020 Toyota Camry as an example. The owner’s manual recommends an oil change every 5,000 miles using 0W-16 motor oil with an “SN” or newer rating. Printed on the label of a bottle of oil is the weight in big bold characters. Also on the label is the API “donut” seal that reveals the API rating for that product. Match both the weight and rating to what your owner’s manual recommends. Because 0W-16 motor oil is extremely light weight, it will only be available as a synthetic.
The last consideration is the brand. You have probably heard the opinions of your neighbors, friends, or family members who each recommend one brand over the other. How do you choose? Do you listen to them, or maybe rely on whatever the quick oil shop down the street chooses for you? Well, again, it is kind of like those golf clubs. If you stick with a reputable brand of club, you are not going to get a bad set. You are going to get good results as long as the length and lie are set up for your swing. Likewise, if you stick to major oil brands – as long as the weight, rating, and type are correct – you are not going to go wrong.
Sure, each manufacturer will have a different additive package that gives one advantage or another, but all will successfully lubricate your engine. What you want to stay away from is a cheap knockoff, whether you are a golfer or a motorist. Avoid no-name brands that may not put the same research and development into their products. You are simply not going to go wrong using the correct oil from a major brand like Castrol, Valvoline, or Mobil.
So don’t worry about the slick marketing ads or your uncle’s opinion. And don’t worry if terms like shear rate, gelation, and oil volatility are lost on you. You can find all the information you need in your owner’s manual.
Columbia Auto Care & Car Wash | Author: Mike Ales | Copyright
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