The motor oil that you use in your car today utilizes viscosity (which is the thickness of the oil) to help push car oil into the extremities of the engine, providing maximum protection against engine part wear and excessive heat. In the past, oils for cars used the term “weight,” such as a 10 Weight-30 oil, to define the same thing that the term viscosity means today.
Before the introduction of synthetic motor oil, vehicle owners had to rely on oil formulations with only one viscosity. This helped alleviate the problems associated with the difference in thickness between the colder winter months and warmer summer months. Mechanics used a lightweight oil, such as a 10-weight for colder weather. During the warmer months of the year, a 30- or 40-weight oil prevented the oil from breaking down in the increased heat.
Multiviscosity oils solved this problem by providing a better flowing oil that remained thin when the weather turned cold while also thickening as the temperature rose. This type of oil provides the same level of protection for vehicles year round. So, no, vehicle owners do not need to change their motor oil for hot or cold weather.
How multiviscosity oil works
Multiviscocity oils represent some of the best motor oil for cars, because it provides protection for engines in a variety of different temperatures. The multiviscosity oil uses special additives, called viscosity improvers, that expand as the oil heats up. This expansion helps provide the viscosity needed at higher temperatures.
Once the oil cools down, the viscosity improvers shrink. This ability to adapt the viscosity to the temperature of the oil makes multiviscosity oils more effective compared to older motor oils, which vehicle owners had to change out according to the season and temperature.
Signs that you need to change your motor oil
Today's motor oils last longer and help protect engines from deposits and leaks no matter the temperature. Regardless of their longevity, the motor oil in a vehicle eventually needs to be changed. Look for the signs that a vehicle's motor oil needs changing to protect your engine, including:
An engine running louder than normal could indicate it needs an oil change. Engine parts rubbing together can cause excessive engine noise. Ask a mechanic check the oil level and change or add oil in this case, in addition to replacing the car oil filter if needed.
The Check Engine or Oil Light comes on and remains lit. This indicates a problem with the engine or oil level. Have a mechanic run a diagnostic and check the oil level when this happens.
When a mechanic reports that the oil looks black and gritty, it is definitely time to have the mechanic change the oil.
Smoke from the exhaust pipe when it is not cold outside can also indicate a low oil level. Ask a mechanic to check the level and either bring it up to the proper level or change it.
Most mechanics apply a sticker somewhere inside the driver-side door when changing the oil to let vehicle owners know when to change it again. Following a regular maintenance schedule and changing your vehicle’s oil at regular intervals ensure that a vehicle engine continues to run in prime condition. By using a multiviscosity oil, vehicle owners ensure that they use the best car motor oil to protect their engine.
This article originally appeared on YourMechanic.com as Do I Need to Change My Motor Oil for Hot or Cold Weather? and was authored by Cheryl Knight.