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10w30 vs. 5w40: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on March 26, 2024
10W30 is a multi-grade oil with a viscosity of 10 in cold and 30 in heat. 5W40 is thinner at cold (5) and thicker at heat (40), versatile for varying temperatures.

Key Differences

0W30 is a type of motor oil where '10W' indicates the viscosity at low temperatures, and '30' signifies its viscosity at higher temperatures. In contrast, 5W40 oil has a lower viscosity rating of '5W' in cold conditions, making it thinner when cold, and '40' for high-temperature viscosity, indicating it's thicker under heat compared to 10W30.
The 'W' in 10W30 stands for winter, highlighting its suitability for colder conditions, but with a higher cold viscosity than 5W40. 5W40 oil, with its lower winter viscosity rating, offers better cold start performance and protection in very low temperatures than 10W30, making it more suitable for colder climates.
10W30 oil is often recommended for engines that operate at moderate temperatures, providing a balance between thickness and flow. 5W40, due to its broader range, is more versatile, suitable for both very cold climates and higher engine temperatures, offering a wider operating range.
Vehicles with higher mileage or older engines may benefit more from 10W30, as its thicker nature at lower temperatures can better protect worn components. 5W40, being thinner in cold, is often preferred for newer, high-performance engines, where rapid oil flow at start-up is crucial.
In terms of fuel efficiency, 10W30 can sometimes provide better results in mild climates due to its adequate thickness, reducing oil consumption. 5W40, with its wider range, is often chosen for its overall protection in varying temperatures and conditions, including extreme cold.

Comparison Chart

Cold Temperature Viscosity

Higher (10W)
Lower (5W)

High Temperature Viscosity

Medium (30)
Thicker (40)

Best Suited Climates

Extremely cold to moderately hot

Recommended for

Moderate temperature engines, higher mileage vehicles
Newer, high-performance engines

Fuel Efficiency

Better in mild climates
Versatile across varying temperatures

10w30 and 5w40 Definitions


A motor oil with moderate viscosity, suitable for average temperatures.
He used 10W30 oil for his sedan, as recommended by the manufacturer.


Engine oil with a viscosity rating of 5 in cold and 40 in high temperatures.
His sports car requires 5W40 oil for its high-performance engine.


A lubricant offering balanced protection for many standard vehicles.
Choosing 10W30 ensures good engine health for most of the year.


A motor oil providing excellent protection in very cold climates and during high engine stress.
The mechanic advised using 5W40 for the upcoming winter road trip.


Engine oil rated 10 in cold temperatures and 30 in hot conditions.
My mechanic suggested 10W30 for optimal performance in spring and fall.


A multi-grade oil that is thinner in the cold and thicker in heat, suitable for extreme conditions.
In the freezing winter, switching to 5W40 can offer better engine protection.


A common viscosity grade for everyday driving needs.
10W30 is a reliable choice for drivers with typical commuting patterns.


A lubricant designed for a wide range of temperatures, providing versatile protection.
To prepare for both summer heat and winter cold, she filled her engine with 5W40.


An oil type ideal for older engines and moderate climates.
For his vintage car, John always prefers 10W30 oil.


An oil ideal for newer, high-performance vehicles, ensuring rapid flow at start-up.
For his turbocharged engine, 5W40 was the recommended oil type.


What does 10W30 mean in oil?

It's a multi-grade oil with a viscosity of 10 in cold temperatures and 30 in hot.

Why choose 5W40 over other oils?

For its versatility in both cold and hot temperatures, especially in high-performance engines.

Can 10W30 be used in all engines?

It's suitable for many, but always check the vehicle manufacturer's recommendation.

What's the main difference between 10W30 and 5W40?

The viscosity in cold and hot temperatures, affecting suitability for different climates and engines.

Does 10W30 oil improve fuel efficiency?

It can, particularly in vehicles operating in mild climates.

Is 5W40 better for cold starts?

Yes, its lower cold viscosity aids in better performance during cold starts.

Does 5W40 oil last longer than 10W30?

Not necessarily; oil longevity depends on driving conditions and engine type.

Is 5W40 oil good for summer?

Yes, its high viscosity at hot temperatures makes it suitable for summer.

Can I switch from 10W30 to 5W40?

It's possible, but consult your vehicle’s manual or a mechanic first.

Can 5W40 protect engines at high temperatures?

Yes, its higher viscosity at hot temperatures provides good protection.

Can 5W40 oil be mixed with other viscosities?

Mixing oils is not recommended; always use the specified grade.

Why is 5W40 preferred in high-performance engines?

Its lower viscosity at cold temperatures ensures quick lubrication during start-ups, essential for high-performance engines.

Is 10W30 oil thicker than 5W40 in winter?

Yes, 10W30 is thicker at lower temperatures compared to 5W40.

Does 5W40 improve engine performance?

It can, especially in providing adequate lubrication in varying temperatures.

Is 10W30 good for cold climates?

It's adequate, but 5W40 might be better for very cold conditions.

What vehicles typically use 10W30?

Many standard, moderate-temperature vehicles, including older models.

How often should I change 10W30 oil?

Follow your vehicle's manual or every 3,000-5,000 miles as a general rule.

Is 10W30 suitable for high-mileage cars?

It can be, particularly for older engines requiring thicker oil at lower temperatures.

Is 5W40 recommended for diesel engines?

It's often used in diesel engines, especially in extreme weather conditions.

What season is best for using 10W30?

Spring and fall, or generally in milder weather conditions.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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