Should I Use Thicker or Thinner Oil This Winter?

In a nutshell: It depends. Some say yes, and some say no. However, the manufacturer’s recommendation for oil generally covers warm and cold temperatures. 

You can check for the manufacturer’s recommendations in your owner’s manual. Most of today’s vehicles require 5W20, 5W30, 10W20, or 10W30 oil as the manufacturer designed the engine to operate most efficiently with a combined oil viscosity.

When it’s time for an oil change, Little Wolf Automotive in Plover, WI has various oil types on hand for all different vehicle makes and models. We do so since every vehicle has different oil grade and viscosity requirements.

Should I Use Thicker or Thinner Oil This Winter? | Little Wolf Automotive in Plover, WI. Image of a mechanic’s hand in the act of pouring fresh oil to a car engine.

Oil Grades and Operating Temperatures

In the old days, when oil had one grade (such as SAE-30), it was more important to use a thinner oil during the colder months. 

Multi-grade oils are now common nowadays and come with a standard notation. The numbers on the bottle will tell you the oil viscosity (the oil’s thickness). The first number is the viscosity at 0°F; the second is at the engine’s operating temperature of 212°F. The “W” between the numbers denotes “winter.” 

The lower the first number, the thinner the oil is when cold outside. Thus, 5W30 is thinner in winter than 10W30. 5W30 is suitable for temperatures as cold as -20°F and up to 100°F in summer. 10W-30 is good to 0°F and up to 100°F in summer.

What a Lower-Viscosity Oil Does to Your Vehicle

Lower-viscosity oil is thinner than higher-viscosity oil. The two major reasons you would use lower-viscosity oil during the winter include making cold starts easier and providing as much protection to the engine as possible during startup.

Lower-viscosity oil travels more easily since the cold conditions can’t thicken it. However, it becomes so thin to the point it provides less protection to the moving parts in the engine—at least while the engine is cold. 

As the engine warms up, though, the oil becomes thicker, thanks to the properties of a dual-viscosity oil.

The Dangers of Using a Thicker Oil During the Winter

While thicker oil will give the engine better protection, it gets even thicker during the winter. 

Thicker oil means more resistance. This means it’s harder to start the vehicle and harder for the oil to get into the oil galleys and protect the engine’s internal parts. 

These engine parts have mere thousandths of an inch between each other. This means it won’t take very long for unprotected parts (such as pistons and rings) to expand. It would be the same as running your vehicle without oil—it will freeze up sooner rather than later.

Have Your Oil Changed Properly at Little Wolf Automotive in Plover, WI

For best results, use only oils with the manufacturer-recommend viscosity. At Little Wolf Automotive in Plover, WI, we’ll always use the proper oil when doing an oil change in winter. 

Stop by our express lube shop for an oil change, and we’ll make sure your vehicle is in good running condition. We are conveniently located at 2550 Plover Road, Plover, WI 54467. Our telephone number is (715) 883-5111.