10W30 vs 10W40

Viscosity:

• 10W-30: Thinner at operating temperatures compared to 10W-40. Provides less resistance, which can improve fuel efficiency.
• 10W-40: Thicker at operating temperatures, offering more protection and a thicker oil film, which is beneficial under high stress.

Temperature Performance:

• 10W-30: Suitable for moderate to warm climates. Provides good protection and performance in typical driving conditions.
• 10W-40: Better for high temperatures and extreme conditions. Provides enhanced protection in hotter climates or under heavy loads.

Engine Suitability:

• 10W-30: Often used in modern engines designed to run efficiently with a thinner oil. Offers a balance of performance and fuel efficiency.
• 10W-40: Commonly used in older engines, high-performance engines, or engines that require extra protection due to high temperatures or heavy use.

Summary:

• 10W-30: Ideal for general use in moderate climates and for engines that benefit from slightly lower viscosity for improved fuel economy.
• 10W-40: Better for high-temperature conditions and for engines that require thicker oil for enhanced protection and durability under stress.