Back to all

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

January 5, 2025

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."

Courtesy Auto Repair Plus
967 Bon Air Ave
Tiffin, Ohio 44883
419-443-0797
http://www.courtesyautorepairplus.com

More articles from Courtesy Auto Repair Plus

Cool Running in Tiffin

April 19, 2026

Unless you live in Death Valley, you really don't hear much any more about cars overheating. That's because cooling systems in vehicles have been much improved. That doesn't mean you can't overheat your vehicle engine, though. Without proper preventive maintenance, you could still find yourself... More

Courtesy Auto Repair Plus Engine Air Filter Replacement

April 15, 2026

When your experienced Courtesy Auto Repair Plus technician changes your oil, he will also inspect your air filter. You shouldn't need a new air filter at every oil change, but you will need to change it regularly. Heed your technician's auto advice if they tell you to change your air filter.An ... More

Shifty Letters PRNDL (Transmission)

April 14, 2026

You probably figured out those shifty letters. They're what you see on your automatic transmission shifter and stand for Park, Reverse, Neutral, Drive and Low. Your automatic transmission is one of the great automotive inventions; here are some ways you can keep yours working well. Maintain yo... More