Q: Can I use full synthetic oil in a 99 mercury Sable 3.0dohc

As you may know, there are a multitude of engine oils on the market all claiming to be the "best" and prolonging the life of your car’s engine. One of the main questions you will be asked when changing your oil is whether or not you want a conventional oil or a synthetic oil. Synthetic vs conventional oil is one of the most debated myths surrounding the topic of oil changes. Contrary to popular belief, it will not hurt your engine when switching from synthetic to conventional or vice versa. In fact, Synthetic blend oils are actually a mix of conventional oils and synthetic oils. It is recommended that you use the same oil to top off when needed, giving you the best protection from the oil you have chosen to use in your vehicle. Many synthetic oils are made up of a base oil of approximately 80%, with other additives making up the remaining 20%. The main difference between the molecules in synthetically engineered oils and conventional oils are the uniformity of the molecules. The molecules found in most conventional oils differ in shape, size and impurity. The type of oil that should be used for a specific application depends largely on the driver’s driving habits, the environment in which the car is driven, the mileage on the car’s engine and the limits that the engine may be pushed to.

The other question you will need to answer when changing your oil is the kind of viscosity your engine requires. Viscosity is the thickness of the oil at certain temperatures. Generally, when the weather is colder outside you will want a thinner oil to allow the oil to flow easier through the motor allowing it to properly lubricate parts. When the weather is hotter outside, you will want a thicker oil to prevent it from what is called “thermal breakdown” and to keep it layering the internal engine parts with the proper lubrication. I would recommend having an expert from Your Mechanic come to your home to perform an oil change service on your car to determine the best option for your vehicle.