Back to all

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

March 22, 2026

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."

Car Fix Libertyville
311 South Milwaukee Avenue
Libertyville, IL 60048
8478738044
http://carfixlibertyville.com

Need Service?

Request a Quote

More articles from Car Fix - Libertyville

That Squeal is Telling You Something (What Causes Squealing While Steering)

March 29, 2026

If you hear a squealing noise when you turn your vehicle, it's trying to tell you something is wrong. After all, it never made that noise before, right? The sound you hear may becoming from a few sources. Let's take a look (or a listen) to some of the possibilities. First, you almost certainl... More

How Much Does It Cost? (Variations in Vehicle Repair Costs)

March 15, 2026

Ever wonder why it costs so much more to fix a similar problem in two different vehicles? Let's say you now own an SUV and before that, you owned a car. Your SUV's air conditioning system needs a new evaporator, but the cost for the new one is way more than you remember it was for your car. How... More

Your Vehicle is Talking to YOU (Service Warning Signs)

March 8, 2026

Your vehicle may be like that famous battery bunny, the one that just keeps going and going. But while it may seem sometimes like you never need to take your vehicle in to be worked on, there are some things you should keep your eyes, ears and nose out for. They are warning you about something t... More