Replacing 0w16 oil, how to choose？

I want to switch to 0w16 oil or 0w20 oil, but I'm not sure if it's suitable. How should I choose motor oil for new and old cars?

0W16 is an ultra-low viscosity fully synthetic motor oil that meets API SP and ILSAC GF-6B standards. Its core features are excellent low-temperature fluidity and strong fuel economy, but it has relatively low high-temperature, high-shear viscosity.
0W-20 is a fully synthetic motor oil that meets API SP and ILSAC GF-6B standards, but 0W-20 typically meets the fuel economy and protection requirements of GF-6A.

What are the specific differences in performance between 0W16 oil and 0W20 oil?

The core differences between 0W-16 and 0W-20 motor oils lie in their high-temperature viscosity (HTHS value), fuel economy, and applicable scenarios.

1. High temperature viscosity：

0W-16: High-temperature, high-shear (HTHS) viscosity is typically 2.3–2.6 mPa·s.
0W-20: HTHS value is 2.6–2.9 mPa·s.

(A higher HTHS value means a thicker oil film at high temperatures, which can better resist direct friction between metal parts and is suitable for high-load or high-temperature operating conditions.)

2. Fuel economy：

0W-16: Due to its lower viscosity, engine oil pumping resistance is reduced, resulting in improved fuel economy.
0W-20: With slightly higher viscosity, fuel economy is slightly inferior to 0W-16, but still superior to higher viscosity motor oil.

3. Applicable vehicle model：

0W-16: Primarily suitable for new Japanese precision engines (such as Toyota's TNGA architecture and Honda's 1.5L naturally aspirated/hybrid engines), which have extremely small component clearances (only 0.1-0.3 microns) and require low-viscosity engine oil to quickly form an oil film.
(Not recommended for older engines (over 100,000 kilometers) or high-load vehicles (such as performance cars or off-road vehicles), as the oil film may be too thin, leading to wear.)

0W-20 has a wider range of applications, including:New Japanese cars (such as Toyota Camry and Honda Accord) that balance economy and protection performance.
(Vehicles with less than 60,000 kilometers: At this point, engine wear is minimal, and 0W-20 can provide sufficient protection.)

4. Protective performance：

0W-16: The advantage lies in its low-temperature fluidity, but its “long-term effectiveness” at high temperatures is slightly weaker, making it suitable for moderate driving condition.
0W-20: Compared to 0W-16, it provides more comprehensive high-temperature protection and can better resist oil film rupture caused by engine overheating.

How can I determine whether 0W-16 motor oil is suitable for my driving habits?

First, we need to determine the condition of our car. Based on the engine viscosity requirements in the vehicle manual and the information above, we can judge whether our vehicle condition is suitable and then decide whether to use 0w-16 motor oil. We should also observe the following condition:

Observe the engine's operating condition: If, after switching to 0W-16, the engine sounds smoother, vibrates less, and delivers power more smoothly without any jerks, it indicates that the oil can quickly form an effective oil film and effectively control engine resistance. This is suitable for your driving habits.
If the sound becomes muffled, vibration increases, the throttle feels heavy, and acceleration is weak, it may be due to an oil film that is too thin to withstand high-load friction, making it unsuitable for aggressive driving. Low oil viscosity can reduce power transmission efficiency, so consider switching to a higher viscosity.