The way you take care of your car's engine may change as it gets older and the mileage adds up. For instance, you might switch to a different, more effective oil to increase your engine's protection against friction and sludge -- two forces that could spell disaster for its longevity.

Synthetic oils offer plenty of advantages over conventional blends, but there are also plenty of rumors surrounding how they perform in older engines, especially those designed with conventional oils in mind. The following takes a look at three common myths about synthetic oil and the truth behind those myths.

Myth #1: Full Synthetic Oil Isn't Compatible With Older Engines

Contrary to popular belief, synthetic oils are made from the same crude oil as conventional oils. What actually separates them is the refinement process that turns crude oil into the engine oil you use in your vehicle.

Synthetic oils are put through a more thorough refinement process that strips away more impurities and adds chemically engineered molecules to the mix. Synthetic oils are also required to meet the same American Petroleum Institute (API) and Society of Automotive Engineers (SAE) specifications as conventional oils.

In short, there aren't any major differences that would make synthetic oil a no-go for an older engine. As long as your chosen synthetic oil is the correct weight for your vehicle and it meets both API and SAE standards, you can safely use synthetic oil in older vehicles.

Myth #2: Synthetic Oil Can Make Engine Problems Worse

You may have heard stories about car owners switching from conventional to synthetic oils, only to experience oil leaks and other unexpected problems. From these stories rose the myth of synthetic oils damaging engine seals and gaskets. However, it's not the oil itself that's responsible for older engines experiencing leaks after a switch to synthetic oil.

Synthetic oil won't cause your engine's seals and gaskets to deteriorate, but it can uncover existing leaks that were otherwise hidden by conventional oil. Conventional oils feature unevenly sized molecules and impurities that can't pass through the microscopic cracks and gaps in seals and gaskets. Synthetic oils, on the other hand, feature uniformly sized molecules with zero impurities that can pass through those areas.

Deposits left behind by conventional oils can also act as seals, preventing oil leaks as long as those deposits are left undisturbed. Synthetic oils contain detergents that can strip away these deposits and uncover existing oil leaks that would otherwise remain hidden.

As long as your engine's seals and gaskets are in good shape, you won't have to worry about any leaks while using synthetic oil. If your engine leaks oil after switching to synthetic oil, then you'll likely have the same problem with conventional oils later on.

Myth #3: Once You Go With Synthetic Oil, You Can't Switch Back

Another all-too-common myth is that once you've switched to synthetic oil, you won't be able to switch back to conventional oil. As mentioned before, the only major difference between conventional and synthetic oil is the refinement process. You can safely mix synthetic oil with conventional blends without causing any damage to your engine.

While mixing synthetic oil with conventional oil won't hurt your engine, you won't get the full performance benefits of synthetic oil. If you want to get the most out of your vehicle, drain all of the conventional oil out of the engine before adding synthetic oil. Don't forget to replace your old oil filter with a fresh filter. Depending on the number of deposits and other impurities in your engine, your first oil change on synthetic fluids may come sooner than expected. Get in touch with a local auto service, such as Furgersons Garage, for more information.