The sticker in the corner of the windshield has been nagging you for weeks to get an oil change. You take your car to your mechanic, and an employee asks you what you want them to use in your vehicle. You stare back blankly like a deer caught in the headlights thinking you should have an answer, but all you can come up with is “oil.”

If this experience sounds familiar, you are not alone. There are many types of motor oil, from full synthetics to good, old, conventional motor oil. Not sure what all the numbers on the bottle mean? We can help you understand the differences between all your motor oil choices and which is the best choice for your vehicle.

Are You Putting the Wrong Oil in Your Car?

(SinayKata / pixabay)

Four Options

To make things less confusing, we’ll start by narrowing the field by composition, which leaves us with four main types of oil.

1. Synthetic

First developed in 1929 as an alternative to conventional oils, synthetic oils often contain refined mineral oil derived from crude oil, a natural product. However, oils in this group are highly refined and chemically engineered for higher performance at extremely high and low temperatures. The particles in synthetic oil are more uniform in shape and size, allowing it to flow freely, lubricating engine components. Synthetic oils contain very few impurities and do not need to be changed as often.

2. Synthetic Blend

As the name suggests, these oils are a mixture of synthetic oil and conventional oil. Because it is a mixture, these oils cost less than fully synthetic oils while still offering excellent performance at low temperatures. Compared to conventional motor oils, synthetic blends provide more resistance to oxidation. Blends are a popular choice for light trucks and SUVs, as they provide superior engine protection when carrying heavy loads.

3. High-mileage

Is your car getting up there in years or miles? This oil is formulated for use in vehicles with 75,000 miles or more on the odometer. It contains seal conditioners that help prevent rubber seals cracks that lead to oil leaks. Maintaining the seals also keeps the oil from being burned in the engine and producing smoke. Other additives in high-mileage oil help break down and remove oil sludge that builds up in the engine and other components over time. You may want to consider high-mileage oil if you see oil spots underneath your car or hear rattling in the engine. Your trusted Utah auto repair can advise you on the best type for your vehicle.

4. Conventional

This oil is the type that your father and grandfather put in their cars, although it has improved over time. For most everyday driving, this type of oil still fits the bill. It is relatively inexpensive and readily available. However, it does need to be changed more often than synthetic or synthetic blend oils. If you don’t do a lot of driving or push your car to the limit, conventional oil should work just fine.

Oil Rating System

To make it easier to compare the performance of different brands and types of motor oil, The Society of Automotive Engineers (SAE) developed a rating system. This system provides two key pieces of information about the oil in an easy-to-read format. The SAE rating appears in the form “AW-XX,” where “A” represents the oil’s viscosity in cold weather, the “W” stands for “winter,” and the X’s give the oil’s viscosity at operating or high temperatures.

Still sound confusing? Let’s break it down further.

What is viscosity?

Viscosity is the resistance of a fluid to flow. In other words, how thick it is and how much does it resist changing shape to flow. An excellent example of a high viscosity fluid that most people know is honey. At room temperature, honey is slow-moving. If you spill it on the table, it is not likely to make it across the table before you can clean it up. Water, on the other hand, is a low viscosity fluid. It has no qualms about quickly flowing across the table and into your date’s lap before you are up and out of your chair.

Why does oil viscosity matter?

Thicker motor oil with a high viscosity flows more slowly in your car’s system, especially at low temperatures. Because the oil flows slower, it may not lubricate your engine well when you first start it. However, as the oil heats to operating temperatures, the viscosity may decrease, allowing it to flow freely and reducing friction while cooling and cleaning the engine. Thick motor oil is great for cars in desert environments where a thinner oil might become too thin on hot days.

The inverse is true in colder climates. The best motor oils for frigid winters are those with low viscosity. Even before the engine is warm, they can flow throughout the car’s system, lubricating friction points, assisting in engine warm-up, and increasing fuel economy.

For example, an oil with a rating of 0W-30 has a low viscosity of 0 in cold temperatures, but the viscosity increases to 30 at operating temperatures. This type of oil would work better than oil with a rating of 10W-30 in a cold climate.

Which oil is right for my car?

The best source for determining which oil will work best for you is determining what your car manufacturer recommends for your specific vehicle. Your mechanic is also a good source of information. They have experience working on many different makes and models.

Choosing what type of oil to use in your vehicle does not have to be confusing. Using the manufacturer’s recommendations and the SAE’s oil rating system, you can be confident that the oil you choose will protect your engine from damage and corrosion. When in doubt, consult with an expert like the ASE-certified technicians at Burt Brothers. Located all along the Wasatch Front, they are Utah’s largest chain of family-owned automotive repair shops. They believe in treating every customer like family.