What technique can help prevent air pockets in the cooling system when replacing coolant?

The technique that plays a significant role in preventing air pockets within the cooling system when replacing coolant is to bleed the system effectively. Bleeding the system using a vacuum method is particularly efficient because it allows for the complete removal of air from the system, ensuring that the coolant fills all passages and channels without entrapment of air. This is crucial as air pockets can lead to overheating and inefficient cooling performance.

Removing the thermostat is also a common practice during coolant replacement, as it allows for better flow of the coolant and ensures that any trapped air can escape more easily. Although it may seem counterproductive to remove a critical component of the cooling system, doing so temporarily during a coolant change can facilitate a more thorough bleed of the system.

Therefore, both of these techniques can contribute to minimizing the occurrence of air pockets, making the combined approach valid in this context.