How Do We Read Motor Oil Grades

An auto mechanic using a blue funnel to put motor oil into an engine. There is black text that says, "How Do We Read Motor Oil Grades?"What Is It For?

Motor oil provides lubrication to the engine’s moving parts, helping to avoid damage and run smoothly. Changing your oil is essential because the by-products from combustion that are collected in the oil each time the engine runs will have cause a decline in the engine’s performance. While there are more external factors to consider, it is highly encouraged to keep up with regular vehicle maintenance and change your oil every 3-5,000 miles or follow your manufacturer’s recommendation. (We do have premium LIQUI-MOLY motor oil and additives for the different vehicles in your fleet if you want to go the extra mile!)

Viscosity describes the thickness of the liquid. The less viscous something is, the thicker it is, and vice versa.

 

How Do We Read It?

What do the numbers mean? We’ll quickly break down how to read it so you can become better acclimated on how to maintain your fleet vehicles with the correct tools.

Reading the different motor oils always consists of three components: a number, followed by a “w,” and then another number. Here’s an explanation of the following:

  • The first number preceding the “w” denotes the cold weather viscosity. The lower the number, the less viscous the motor oil will be at lower temperatures.
  • The letter “w” itself simply means winter.
  • The second number denotes the hot weather viscosity.

Another way to think of it is how fluid the motor oil is at hot temperatures. Thinner oils reduce the friction in engines and helps them start more quickly in cold weather. Thicker oils maintain oil pressure at high temperatures and loads.

 

Can I Change the Motor Oil Grade Depending on the Changing Weather?

It is essential to consider where the car will be used. Different viscosities were created with different climates in mind; 0w-20 and 5W-30 oils were made for colder climates while 15W-40 and 20W-50 oils were made for hotter.

Different grades of motor oil do have overlaps with what temperatures each grade can operate under. Although, it’s not recommended to experiment with using different oils than what is recommended by the vehicle’s manufacturer.

If the motor oil in the engine is too thick, it does not properly lubricate the engine components, which causes excess resistance when the car starts. Not only is this inconvenient, especially if you live in colder weather, it could even put your life at risk if there is ever an emergency.