
Understanding Oil Viscosity and Types: It’s Not Just About the Numbers
When you open a bottle of motor oil, you might notice numbers on the label like “5W-30” or “10W-40.” But what do these numbers really mean? It’s easy to think they’re just some random codes, but they’re packed with important information about the oil’s performance.
Understanding these numbers and the different types of oil can help you take better care of your car or any machine that uses oil. It’s not just about picking any oil viscosity and pouring it in; it’s about choosing the right one to keep everything running smoothly.
In this piece, we’re going to talk about what these numbers and terms really mean, so you can make smarter choices for your vehicle. Let’s get started:
What Is Motor Oil?
Motor oil is the lifeblood of your car’s engine. It serves multiple purposes: lubricating the engine’s moving parts to reduce friction, cooling the engine by carrying heat away from the parts, cleaning by trapping dirt and debris, and protecting against corrosion. Without oil, the engine’s parts would grind against each other, leading to wear and tear, overheating, and even total engine failure.
But not all motor oils are the same. They come in different types and viscosities, which is where those confusing numbers come in. Understanding these differences can help you choose the right oil for your car, depending on factors like the weather, your driving style, and the specific needs of your engine.

The Basics of Oil Viscosity
The key number you’ll always see on motor oil bottles is the viscosity. Viscosity refers to how thick or thin the oil is. Imagine honey and water—honey has a high viscosity because it’s thick, while water has a low viscosity because it’s thin. Oil viscosity works the same way: it describes how easily the oil flows.
In the oil world, you’ll typically see two numbers separated by a dash, like “5W-30” or “10W-40.” Let’s break down what these numbers really mean.
Breaking Down the Numbers
The first number (5W or 10W): This number is followed by the letter “W,” which stands for “winter.” This number tells you how the oil behaves in cold temperatures. The lower the number, the thinner the oil is at low temperatures, meaning it flows more easily when your engine is starting up on a cold day. For example, a 5W oil is thinner than a 10W oil when the temperature drops.
The second number (30 or 40): This number describes how thick or thin the oil is at high temperatures—typically when the engine is fully warmed up. A higher number means thicker oil, which provides a better cushion for the moving parts of your engine under hot conditions. For instance, a 30-weight oil is thinner than a 40-weight oil when the engine is hot.
So, when you see something like 5W-30, it’s telling you that the oil is designed to be thin enough to flow well in cold temperatures (thanks to the 5W) but thick enough to protect your engine at high temperatures (thanks to the 30).

Why Oil Viscosity Matters
It might seem like the numbers are just random, but they actually have a big impact on your engine’s performance. Here’s why:
Cold Starts: When you start your car on a chilly morning, the oil needs to flow easily to get to all the parts that need lubrication. If the oil is too thick, it won’t flow fast enough, which can lead to increased wear and tear. On the other hand, if it’s too thin, it might not provide enough protection. That’s why using the right oil with the right low-temperature rating is crucial, especially in colder climates.
High Temperatures: When the engine heats up, oil tends to thin out. A thicker oil (higher second number, like 40) will maintain its protective qualities better than a thinner oil (like 30) when things get really hot. This is important for high-performance engines or during hot summer months.
Fuel Economy: Thinner oils tend to reduce engine friction, which can improve fuel efficiency. On the flip side, thicker oils might cause slightly more resistance, which could reduce fuel economy. That’s why many modern cars use lighter oils like 0W-20 or 5W-20 to improve fuel efficiency.
Types of Motor Oil
Motor oil comes in several different types, each suited to specific needs. Choosing the right type of oil for your car can make a big difference in performance and longevity. The main types are:
Conventional Oil: This is the standard, traditional oil that’s been around for a long time. It’s made from crude oil and refined to meet specific requirements. Conventional oil is often cheaper, but it needs to be changed more frequently than other types. It’s suitable for older engines or cars that don’t see much heavy use.
Synthetic Oil: Synthetic oil is a more advanced type of oil. It’s made through a chemical process that allows for more control over the oil’s molecular structure. This means synthetic oils perform better than conventional oils, especially in extreme temperatures (both cold and hot). They last longer, provide better engine protection, and are often used in high-performance or modern engines.
Synthetic Blend Oil: As the name suggests, synthetic blend oil is a mix of conventional and synthetic oils. It provides some of the benefits of synthetic oil (like better protection and performance) at a lower price. It’s a good option for people who want better performance but don’t need full synthetic oil.
High-Mileage Oil: If your car is older and has more miles on it, high-mileage oil might be a good choice. This oil contains additives that help reduce oil consumption and minimize leaks, which can be more common in older engines. High-mileage oils can also help prevent the buildup of sludge and keep seals in good condition.

Choosing the Right Oil for Your Car
Now that we understand oil viscosity and the different types of oil, how do you know which one is right for your car? Here are some key things to consider:
Check the Owner’s Manual: The first step in choosing the right oil is to check your car’s owner’s manual. It will list the recommended oil type and viscosity for your specific engine. Following these guidelines is the best way to ensure your engine runs smoothly and lasts longer.
Weather and Climate: If you live in a region with extreme temperatures, the oil you choose becomes even more important. For cold winters, oils with a lower first number (like 0W or 5W) will flow better at low temperatures. If you live somewhere hot, you might want a thicker oil to protect your engine at higher temperatures.
Driving Style: If you’re someone who drives aggressively or does a lot of stop-and-go driving, you may need an oil that can handle higher stress and temperatures. In this case, synthetic oils or high-viscosity oils could be a better fit.
Age of Your Vehicle: Older cars or those with higher mileage might benefit from high-mileage oil, which is designed to help prevent leaks and reduce wear in aging engines.

Why Haus of Cars Chooses Liqui Moly
At Haus of Cars, we’ve tested and worked with many of the biggest oil brands in the industry. While brands like Castrol and Mobil 1 have strong reputations, we ultimately chose Liqui Moly for one simple reason—superior quality.
Liqui Moly may not have the same mainstream recognition, but among professionals and enthusiasts, it’s known for its advanced formulations and high-performance results. Manufactured in Germany, their oils meet and often exceed industry standards like API SN Plus and ACEA certifications. They also undergo rigorous testing under extreme conditions, ensuring optimal lubrication, engine cleanliness, and wear protection.
What truly sets Liqui Moly apart is its extensive product range, offering highly specialized formulations for different engine types, including high-mileage vehicles, turbocharged engines, and even performance cars. Whether it’s synthetic motor oil, fuel additives, or wear protection treatments, Liqui Moly provides precisely engineered solutions that deliver long-term engine health.
Let Us Help You Keep Your Engine Running Smoothly
Whether you’re looking for expert advice on oil choices, need a full-service maintenance check, or want to restore your car to its prime, our team of passionate car enthusiasts is here to help. Located in the heart of Burnaby, BC, Haus of Cars specializes in everything from mechanical repairs to premium detailing, ensuring your vehicle gets the attention it deserves.
Our experienced technicians, with a particular love for German vehicles, are here to provide personalized service tailored just for you.
Book an appointment today or stop by to see how we can enhance your vehicle’s performance and longevity!