MOTOR OIL MYTHS
You shouldn't use synthetic oil in an older vehicle.
This myth is rooted in the idea that synthetic oil is “slipperier” (lower in viscosity), or not as compatible with seals, and will therefore leak or leak more in places conventional oil might not. Again, completely untrue. Synthetic oils will enhance the engine protection in older vehicles, just as they do for new engines. Always follow the engine oil specification recommended in the owner’s manual.
You need a thicker motor oil for extra wear protection.
This is one of the most common car care myths out there. First off, it is the antiwear additives (ZDDP or “zinc”) in the motor oil formulation that provide wear protection, not the motor oil viscosity grade. Using a motor oil that is too thick may decrease engine efficiency. Many modern and newer vehicles recommend lower viscosity grades for better fuel economy and tighter tolerances. Always follow the viscosity grade recommended in the vehicle owner’s manual.
Synthetic oil is slipperier and causes your engine to leak.
Some drivers believe that synthetic motor oil causes your engine to leak because it is slipperier — this is FALSE! Slipperiness has to do with the motor oil viscosity grade, regardless of type. Synthetic oil will NOT cause your engine to leak. Synthetic motor oil actually provides better protection for your engine at extreme temperatures. Always follow the vehicle manufacturer’s recommendation for engine oil.
High mileage engines just need thicker oil to reduce leaks.
FALSE. High mileage motor oils are specifically formulated for older engines to help reduce oil consumption and contain seal swell additives to help reduce leaks. Always follow the vehicle owner’s manual for the correct viscosity grade.