Understanding Engine Oil

 We've all seen this meme all over the internet and well to be honest, its one of the most intimidating aisles in the auto parts store.. Let's hope we can clarify a few things so it's not so scary. 

Understanding engine oil weights, conventional oil vs. synthetic oil, regular vs. high mileage. Engine oil can be intimidating, technological improvements have led to so many new types, weights and brands. Understanding what it all is can really help you understand what you need and why you need it. 

What all these numbers mean and why there’s a W in the middle. Oil is rated using reference numbers indicating the viscosity rating, or weight, of the oil. Viscosity can be simply thought of as its “thickness” or a measure of its resistance to flow. The most commonly used oil is what is called multi-grade, meaning it includes two viscosity grades, the first number indicates the base grade viscosity at cold temperatures (the “w” after the first number means “winter”) and the other indicating the viscosity at warmer temperatures. The basic series is 0, 0W, 5, 5W, 10, 10W, 20, 30W, 30, 40W, 40, 50 and 50W. The most commonly seen weights used are 5W20, 5W30, 10W30 and 10W40. Oils starting with a 5W are much thinner and often seen in newer cars, oils with a 10W or higher are thicker and often seen in higher mileage cars. 

Result of a quick google search - i have a 2000 VW Jetta 1.9L TDI requiring VW 505.00 standard oil

Picking a brand. With so many different brands available to choose from it can be very difficult to know if what you are buying is the right oil for your car. What does it matter? Well, a number of years ago, the standard for oil was very simple and basic. As technology improved and efficiency and emissions standards became stricter, the major auto manufacturers began developing their own standards for engine oil to meet the needs and requirements of the specific engines they build. What does this mean to you? If I have a Volkswagen, do I have to buy oil from Volkswagen? Or Mercedes? Or BMW? Or Honda? Or GM? No you don’t. What you have to do is your research. In addition to making sure you are using the proper weight oil defined by your manufacturer, you have to make sure that the oil you are using is approved by your manufacturer for your vehicle. In fact, this is more important that having the proper weight.  For example, I own a Volkswagen which runs a 5W30 synthetic oil. However, I cannot use just any 5W30 synthetic oil. Volkswagen states that I need to use a engine oil that meets their VW 505.00 standard.

When purchasing oil for my car, I need to read the back of the container and make sure that it conforms to that standard before putting it my car. How do I know what my manufacturer’s standard is? Well, your owner’s manual is the first resource, google always works or you could contact us and we have that information readily available and can provide you with the brands that your manufacturer approves. 

This is the label from the oil i use in my car clearly indicating it meets the VW standard required.

Why is this so important? Well, keep in mind the amount of research and development that goes into building a engine for maximum lifespan and efficiency. Your engine is a very volatile environment that faces extreme pressures and temperature changes over its entire life. Your auto manufacturer developed its own standard designed specifically for the increased life span and efficiency of its engine. There are a variety of detergents and additives added to reduce carbon build-up, increase life span of the many moving parts and cool the various metals used to the proper operating temperature. All of these things lead to longevity and maximum power output as well as fuel efficiency. If you are not using the proper oils, all of these sensitive factors will be compromised, potentially resulting in catastrophic failure over a long period of time. That being said if you have no oil in your car, any oil will suffice in a pinch, but make sure you change to the proper oil as soon as possible. 

Conventional vs. Synthetic Oil

Most newer cars are built to run a synthetic oil as it has a higher viscosity (its thinner), it contains more additives and detergents and can run longer spans of time with less frequent changes needed. If you are not sure if your vehicle takes a synthetic oil, do your research on what the manufacturer specifies. Conventional oil is more commonly found in higher mileage vehicles as it is usually a little thicker. Over time, engine seals can shrink or dry which will allow a much thinner oil to leak out. Using a thicker oil will slow these leaks down. Additionally, over time, clearances built into your engine will expand and using a thicker oil will compensate for these differences. There are special oils designed specifically for higher mileage engines as well. If you are unsure of which one of these options you should choose or if you should consider switching from one to the other, send us an email or give us a call and we can help you decide what’s best for your engine.

Bill Marino Auto Repair