Back to all

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

July 14, 2024

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 St. Johns
2770 Racetrack Rd.
St. Johns , Florida 32259
904.230.3363

More articles from Tuffy St. Johns

Rotation Explanation (Tire Rotation Patterns)

May 18, 2025

You may notice that when you get your vehicle's oil changed, your service adviser may recommend that you have your tires rotated at the same time. The reasons are simple. That will allow your tires to wear more evenly and reduce the noise your tires make as you drive down the road. There are di... More

The ?Man-Made? Engine Oil (Synthetic Oil Change)

May 11, 2025

If you own a newer vehicle, your vehicles manufacturer may require that it use synthetic oil instead of conventional oil. Synthetic oils are more stable, dont break down as easily, and provide better engine protection than conventional oil. All those things can prolong the life of your engine an... More

Getting Off to a Running Start (Starter Replacement)

May 4, 2025

When you start your vehicles engine, theres another motor that makes that whole process possible. Its called the starter, and its a small electric motor that gets your vehicle running. As you can imagine, its quite a chore for a little electric motor to turn over the big engine that powers you... More