Differences Between Shell Helix Ultra 5W30 and 5W40 Engine Oil
2 Answers
Differences lie in high-temperature viscosity, fluidity, and usage environments. Differences between 5W30 and 5W40: Different high-temperature viscosity: 5W40 has higher viscosity, providing better high-temperature protection performance and slightly better sealing. Different fluidity: Winter oil grades are 0W, 5W, 10W, 15W, 20W, and 25W. The symbol W stands for winter, and the smaller the number before W, the lower the low-temperature viscosity, the better the low-temperature fluidity, and the lower the applicable minimum temperature. Different usage environments: The difference between 5W-40 and 5W-30 is only the latter number. 40 can be used in summer environments with temperatures below 40 degrees, while 30 can be used in environments with temperatures below 30 degrees. Precautions: Gasoline engine oil cannot be used in diesel engines to avoid accelerating diesel engine wear. Gasoline engine oil and diesel engine oil should in principle be used separately. Only when the automobile manufacturer has substitution instructions or indicates that it is a universal oil for gasoline and diesel engines can it be substituted or used within the indicated grade range.
As an average driver, I've found the key difference between 5W30 and 5W40 lies in their viscosity at high temperatures: 5W30 is thinner, delivering better fuel efficiency and smoother driving, especially noticeable through quieter engine operation during hot summers or highway cruising (though cold starts feel similar). Having used Shell Helix Ultra 5W30, I can confirm it's perfect for new cars - saving hundreds in annual fuel costs. The thicker 5W40 offers superior high-temperature protection, making it ideal for older vehicles or those frequently driven in hot climates to prevent accelerated engine wear. Shell's synthetic oils maintain consistent quality, but the crucial factor is matching viscosity to your vehicle's condition - newer models shouldn't use overly thick oil as it wastes fuel and dulls acceleration response. Regular oil changes are vital; I perform checks every 5,000 km to maximize engine longevity.
