Back to all

Oil's Well That Ends Well (Oil Change Grades and Weight)

June 25, 2023

Changing your oil regularly is one of the most important things you can do to keep your vehicle running well.  And knowing the right type of oil to use is also very important. 

Engine oil is classified by weight, but it doesn't refer to how much the oil would weigh if you put it on a scale.  It refers to viscosity, or how easily the oil flows through the engine.  Most engines operate normally at around 210°F/99°C.  The viscosity, or weight, is assigned a number by how well it flows at that temperature.  The lower the number, the more freely it flows. 

Most vehicle engines use what's called a multigrade oil which behaves differently in different temperatures. Multigrade oils have a "W" in their viscosity number that you may have seen on a bottle of oil, something like 5W30.  The W stands for winter and shows how freely it flows in colder temperatures.

That means a 5W30 oil will behave like a 5 weight oil in lower temperatures (less viscous or thinner) and a 30 weight oil in warmer temperatures (more viscous or thicker).  That's important on a cold day because the oil needs to behave like a thinner oil when you start your engine since it need to lubricate engine components immediately to protect the metal components. Then as the engine warms up, it behaves like a thicker oil to prevent friction among those parts.  Pretty neat trick, right?

The type of oil you use can differ depending on what type of climate you operate your vehicle in and how your vehicle is used (carrying big loads, towing, etc.). Your owner's manual contains several different recommendations based on these factors.  Your service advisor can recommend the right oil for your needs.  Like Shakespeare said, "Oil's well that ends well."

Tuffy Lake In The Hills
59 West Acorn Lane
Lake In The Hills, Illinois 60156
847-854-9850

More articles from Tuffy Lake in the Hills

Your Vehicle's Other Power Plant (Alternator Replacement)

September 7, 2025

Your vehicle's engine is probably the first thing that comes to mind when you think of a power plant. But it has another power source that is vital as well: the alternator. The alternator is what puts out the electricity that powers such things as your lights, power windows, sound system, and na... More

Giving CV Joints the Boot! (CV Joint and Boot Replacement)

August 31, 2025

Ever wonder how your vehicles transmission is connected to your wheels? After all, when you hit a pothole or some other uneven part of a roads surface, there has to be something that can maintain the connection between the transmission and the wheel yet keep everything moving at the same speed. ... More

Greeted by a Screech (Loud Noise when Starting Vehicle)

August 24, 2025

No one likes to be greeted in the morning by having someone screech at you. The same goes for a loud, high-pitched noise your vehicle greets you with every time you start the engine. If you're wondering if that's normal, no, it isn't. And it is worth getting checked out. The good news is that... More