Hello everyone, and welcome. In this video, we’re going to be discussing frequently asked questions and myths surrounding motor oil. Now rather than me blabbering and trying to convince you of what is true. I’m going to be asking Shanna Simmons, who is a research engineer for Shell. Who has access to the information and research needed to answer these questions. And hopefully she can put some of these myths to rest. So my first question is, “I put 5W-30 in one of my cars. What does that combination of letters and numbers mean?” Let’s discuss what a multi-grade viscosity really means. So, the 5 is the viscosity grade when it is cold. So, remember the W stands for winter. The 30 is the viscosity grade at the engine’s operating temperature. Engines operate at around 212°F (100°C). Okay, so why should I change my oil? As an engine burns fuel it deteriorates the motor oil. Changing your oil helps to remove harmful contaminates and it replenishes the additives that have been depleted. So, what is the typical composition of motor oil? So this chart shows the typical composition of motor oil. So depending on the formulation, the motor oil will be about 75-90% base oil. The other 10-25% will be additives. So the base oil determines the fundamental properties of the motor oil and the additives help to enhance the base oil, help to protect the base oil and help to protect the mechanical equipment. Ok, now you mentioned oil additives. Are aftermarket oil additives something I should be using? No! Branded products already contain carefully balanced additives for optimal performance. And I’m sure that same logic can be applied to many brands of oil out there. Now, alot of people debate about conventional and synthetic oil. Before we get into that, what is the difference between these two terms? So the base oil can either be conventional or synthetic. If the base oil is conventional it means it’s only been refined from crude oil. If it is synthetic it means it has been through an additional chemically engineered process to give it better properties for use in a motor oil. Okay, so is synthetic oil compatible with conventional oil? And can the two be mixed? Yes. Motor oil labelled a synthetic blend already contains both synthetic and conventional base oil in the formulation. We also carefully test our motor oils with other motor oils to ensure compatibility. A lot of people debate whether or not you can use synthetic oil to break in an engine. Can you? Yes. In fact, a majority of vehicles manufactured today are factory filled with synthetic oil. And many race teams also use synthetic oils to break in their engines. Now, sludge is a term often brought up when talking about engines and oil, what is sludge and what causes it? So, every time your engine is running by-products from combustion build up and contaminate the motor oil. If contaminants build up inside your engine they can set a lot and form sludge. Using low-quality motor oil, neglecting to change your oil and maintenance issues can all lead to sludge forming inside your engine. Now I often get the question, can I use this certain viscosity grade even though the manufacturer suggests another viscosity grade? Why should I use the viscosity grade that the manufacturer recommends? Your engine was designed with the specific viscosity grade in order to lubricate menchanical parts properly. If you use oil that is too thin, you may run into wear issues. If the oil is too thick, engine efficiency may decrease. Always follow your vehicle’s owners manual to determine the correct SAE viscosity grade to use inside your engine. So, a huge thank you to Shanna for helping answer some of these questions and as always if you have any questions or comments feel free to leave them below. Thanks for watching.