What is the Difference between Synthetic Oil and Conventional Oil?

January 27, 2012

When you change your car's engine oil you have a lot of choices, including the use of synthetic oil or conventional oil. Most wonder what the benefits are of using synthetic vs. conventional oil. And if it's really worth the money. Conventional motor oil is a lubricant that is derived directly from crude oil. It has excellent properties that allow it to provide lubrication at high temperatures, as well as maintaining its stability over long periods of time. Synthetic oil actually begins its life as conventional oil and is then modified to improve its protective and lubricant properties. Some blends of synthetic oil are designed specifically to increase the performance and life of high-mileage cars. Others are meant specifically for high-performance engines. Others actually have the ability to increase your car's fuel mileage by using special advanced lubricants. Here is a quick overview of the most common advantages that synthetic oils offer over conventional motor oil:

  • Improved Lubrication - Most synthetic oils have added lubricants that increase the ability of the oil to keep engine parts slick, especially at high temperatures. This decreases wear over the long term, and may make your engine last longer.
  • Better Stability - Synthetic oils are specially engineered to maintain their viscosity (thickness) at higher temperatures and over longer periods of time. This helps you prevent engine wear in several ways. It allows the oil to "stick" to engine parts more readily, providing better wear protection, as well as doing a better job protecting your engine from dry starts. A "Dry Start" occurs when your car has been sitting for an extended period of time. Gravity pulls the oil down to the bottom of the engine, allowing the components at the top of the engine to lose lubrication and run unprotected. By helping the oil maintain viscosity, synthetic additives decrease the effects of "dry starts."
  • Reduced Breakdown - Synthetic oils are less apt to break down which means that many synthetic oils don't need to be changed as often as conventional oils. The more durable properties of synthetic oil also means that your engine is protected better through the whole service interval.
  • Fewer Deposits - As conventional oils break down, they often leave deposits on engine components. Mechanics refer to this as "sludge" or "scaling." This is especially common in engines that run for long periods of time, are driven hard or driven under tough conditions. As conventional oil breaks down, it literally sticks to different surfaces in the engine and "bakes on" just like cooking oil would in a frying pan. Synthetic oils are less apt to do this. In fact, some conventional oils are available that actually have the ability to remove some of these deposits.

The properties that separate conventional oil from synthetics affect your engine in many important ways. But remember that these types of oils are in no way absolutely necessary. Although the properties of synthetic oil are definitely superior, conventional oil will protect your vehicle's engine just fine. The most important thing you can do to keep your car running smoothly is to follow your vehicle manufacturer's recommended service intervals.

Related Questions and Answers

Who are the Most Popular Motor Oil Manufacturers?

Motor oil is classified based on the viscosity number and by manufacturer. Some motor oil manufacturers only make certain types of oil (for example 20W-50). However, the most common manufacturers for motor oil used in a typical automobile are: Castrol, Quaker State, Mobil, Exxon, Havoline, Valvoline, Pennzoil, and Shell. All of these manufacturers create and sell oil typically used in automobiles. There are dozens of other manufacturers but these are by far the most popular.

How Many Different Types of Synthetic Oil are there?

There are two main synthetic oil types available for purchase. Synthetic oil made from a base stock and semi-synthetic oil. Synthetics made from a base stock are created from one of three types of lubricants: polyalphaolefin, synthetic esters or hydrocracked/hydroisomerized bases. Semi-synthetic oils are a blended oil comprised of no more than 30% synthetic base. Synthetic oils typically create less friction and are more stable, often lasting longer than a non-synthetic oil.

Are Synthetic Oil Prices Trending Higher or Lower?

Like crude oil, synthetic oil prices (created from natural esters or other chemicals) are currently trending higher. This is largely due to the notion that crude oil prices affect synthetics. While this is true to some extent, the fact remains that synthetic oils are often devoid of crude oil. However, most people are entirely unaware of this fact, and synthetic oil prices will rise with the price of crude oil, as is the case currently.

Where can I find an Engine Oil Capacity Chart?

An engine oil capacity chart can be found in a number of locations. The simplest place to look is in your vehicles owner's manual. However, many auto part suppliers have this information on hand and will freely distribute it. These are the two best places to get the correct information. Aside from that you should be able to find the desired information on numerous websites. However, information on the Internet is often misleading or incorrect, so it is better to get the oil capacity from your service manual, auto parts dealer, or local dealership, if possible.