Blog Car Care Advice 5W-30 Oil Meaning (+How It’s Different From Other Oils)
Car Care Advice

5W-30 Oil Meaning (+How It’s Different From Other Oils)

Looking for a mechanic near you for maintenance or repair? AutoNation Mobile Service brings the shop to you. Get a free instant quote today.
Get a Quote

5W-30 oil is one of the most popular oil viscosity grades in the market today. It’s ideal for a passenger car, SUV, or light truck since it improves fuel efficiency and overall engine performance.

But what does 5W-30 oil mean?

Read on to explore everything about this oil, including its uses and benefits.

This Article Contains:

What Does 5W-30 Mean in Oil?

The Society of Automotive Engineers (SAE) developed a standard scale to grade motor lubricants and transmission oils by their viscosities. These grades are allotted after a thorough oil analysis and written in the following format: 

5W-30 is a multi-grade oil. Each element in its viscosity grade helps determine how the oil flows over a range of temperatures. 

Here’s what 5W-30 means: 

Next, let’s understand how these grades set each oil apart.

How Is 5W-30 Oil Different From Other Engine Oils?

5W-30 has a lower cold-temperature viscosity compared to other lubricants, like 10W-30 oil and 15W-30. 

Lower viscosity means that the oil doesn’t thicken at a lower operating temperature, offering a better cold startup. Its smooth flow decreases friction among the moving parts, preventing engine wear and reducing oil consumption.

Additionally, 5W-30 has decent high-temperature performance — capable of operating at conditions as high as 212°F. 

But if you live in a region with harsh summers, you should switch to a higher-viscosity oil. 

That’s because 5W-30 motor oil’s viscosity is unsuitable for extreme hot climates. In higher-temperature environments, car engines require thicker oil with proper bearing support and cushioning for your engine’s metal surfaces. As 5W-30 oil is comparatively thinner than other multi-grade oil like 5W-40, it may not lubricate the engine well, leading to increased friction and corrosion. 

Wondering if 5W-30 suits your car engine? 
Let’s have a look.  

What Is 5W-30 Oil Good For?

Being a thin motor oil, 5W-30 is best for people who drive vehicles in colder temperature regions.

Other than that, this oil is perfect for: 

  1. Light-duty diesel cars
  2. Light-duty passenger cars and trucks with gasoline engines    

Note: Although 5W-30 oil works in the above-mentioned cases, you should refer to your owner’s manual to find the specific viscosity requirements of your engine. And if you wish to cross-check if the oil suits local weather conditions, you can consult a mechanic

Now that we understand 5W-30 oil better, let’s look at some common queries about this motor oil.

6 FAQs about 5W-30 Oil

Here are answers to common doubts you may have about 5W-30 oil:

1. Is 5W-30 a Synthetic Oil?

It depends. 5W-30 is available as synthetic, high-mileage, and conventional oil (mineral oil).
Here’s how each type of oil is different:

  1. 5W-30 synthetic motor oil is prepared with extensively refined crude oil and chemically modified petroleum compounds. It contains various additives that improve its lubrication and other basic functions. Due to its formulation, it’s a better lubricant than conventional oil. 
  1. 5W-30 high-mileage oil combines base oils, friction modifiers, and additives to assist high-mileage engines. These additives and modifiers minimize engine wear and reduce the possibility of thermal breakdown.
  1. 5W-30 conventional oil uses a base consisting of refined crude oil. Anti-wear additives are added to the base oil for improved lubrication and better protection. Brand-new conventional or mineral oil usually behaves exactly like 5W-30 synthetic oil, but it deteriorates faster than synthetic engine oil.  

Note: Even though synthetic motor oil is superior to conventional oil, you should check with your mechanic before adding it to your engine.  

2. Is 5W-30 Oil Suited for Heavy-Duty Use?

Yes, but not all variants. Most 5W-30 motor oil products are usually recommended for light-duty gasoline and diesel use. 

While 5W-30 full-synthetic diesel oil from a few brands can handle heavy-duty requirements, in most cases, your engine will struggle if you use 5W-30 for heavy-duty applications continuously. 

For example, using it may accelerate oil breakdown in your engine, leading to inadequate lubrication and increased friction. Eventually, you may notice poor fuel economy and reduced engine performance.

3. Is 5W-30 Oil Suitable for Diesel Engines?

5W-30 oil is suitable for a light-duty diesel engine. But if you own a heavy-duty diesel vehicle, you may want to go for a thicker oil like 15W-40.

A diesel engine combusts at a very high compression rate — much higher than gasoline engines. So, it requires a higher viscosity grade oil that can work under a high-temperature setting while lubricating engine parts.   

4. What Are the Benefits of Using 5W-30 Oil?

5W-30 prolongs your engine’s life and reduces wear. It also provides the following benefits:  

  1. Reduced harmful emissions and chances of thermal breakdown
  2. Improved fuel efficiency and economy
  3. Enhanced engine performance
  4. Better cold starts in lower temperatures

Tip: Consider purchasing motor oil from popular brands to get top-quality products that benefit your car’s engine. This includes Castrol Edge 5W-30 synthetic oil, Valvoline Advanced full synthetic SAE 5W-30, or Mobil 1 ESP 5W-30. 

5. Can You Use 5W-40 Oil Instead of 5W-30 Oil?

Ideally, no. 

5W-30 is a thinner oil that offers better fuel economy and boosts engine performance across different temperatures. However, your car requires a specific engine oil grade. Adding a thick fluid to an engine meant for thin oil without consultation could be bad for your engine.

But here’s an exception: 
You can consider using 5W-40 in older cars when the gap between the bearings and piston rings has increased due to engine wear. In such a case, a higher-temperature viscosity oil like 5W-40 will be good as it provides better protection and lubrication for an engine’s metal surfaces. 

That said, before switching from 5W-30 to 5W-40 oil grade, it’s best to consult a professional

Tip: Always look for authentic products certified by the Society of Automotive Engineers (SAE) and the American Petroleum Institute (API SP) to ensure top engine performance. 

6. What Happens When You Use the Wrong Motor Oil? 

Using incorrect oil won’t immediately affect most cars with a modern engine. That’s because the oil will continue to lubricate the engine components and cushion the moving parts. 

But gradually, you may notice signs like: 

  1. Oil leak: An engine meant for thick oil (heavy-weight oil) will have larger spaces between bearings and other parts. Adding thinner oil in such an engine will affect the oil pressure and eventually lead to a leak. 
  1. Reduced engine performance: Cars that require thin oil (lower-viscosity grade oil) won’t work well with thick oil, as it creates more friction and may lead to a sluggish throttle response.
  1. Overheated engine: Thick oils in engines meant for thin fluids will fail to reach critical engine parts in time, reducing oil pressure and overheating your car’s engine. Due to this high-temperature condition, the heat can even burn the oil.
  1. Increased wear and tear: Adding incorrect oil means your engine parts may not receive sufficient lubrication. This can create more friction, wearing out the piston, oil pump, and other components quickly.   

If you notice any of these signs, schedule an oil change service to switch to a suitable engine oil grade. 

Oil Changes Made Easy with AutoNation Mobile Service

Although 5W-30 engine oil is a popular recommendation for a modern engine, when choosing a multi-grade oil, always refer to your owner’s manual for any specific oil requirements. Still if you’re unsure about using 5W-30 oil grade, contact AutoNation Mobile Service mechanics to check and perform an oil change for your car.

We’re a mobile auto repair solution offering competitive and upfront pricing. We also provide a 12-month | 12,000-mile repair warranty on all services, including changing gear oils.

Contact us to schedule a car service, whether that’s a coolant, brake fluid, or oil change.