A high-quality car water tank needs to have the following characteristics in design and manufacture:

1. High-temperature resistance: The automobile water tank needs to be able to withstand the heat of the high-temperature working environment of the engine, and has good high-temperature resistance and is not easy to deform or crack. High-quality water tanks usually use high-temperature and pressure-resistant materials, such as engineering plastics or aluminum alloys, to ensure that they can still work normally under high temperature conditions.

2. Corrosion resistance: The automobile water tank needs to have good corrosion resistance, which can resist the corrosion of corrosive substances in the coolant and prolong the service life of the water tank. High-quality water tanks usually adopt anti-corrosion treatment or special coating to improve their corrosion resistance.

3. Sealing performance: The automobile water tank needs to have good sealing performance, which can effectively prevent the coolant from leaking or evaporating and maintain the pressure balance and stability of the system. High-quality water tanks usually adopt high-precision manufacturing technology and seals to ensure that the water tanks are closely connected with other system components without leakage.

4. Structural strength: The automobile water tank needs to have sufficient structural strength, which can withstand external forces such as engine vibration and road bumps, and is not easy to deform or rupture. High-quality water tanks usually adopt reinforced design or structural optimization to improve their structural strength and durability.

5. Safety performance: The automobile water tank needs to have good safety performance, which can effectively protect passengers and vehicles in case of collision or accident, and will not cause secondary damage to vehicles. High-quality water tanks usually use materials and designs that meet safety standards to ensure that the safety performance meets the requirements.

To sum up, a high-quality automobile water tank needs to have the characteristics of high temperature resistance, corrosion resistance, good sealing performance, sufficient structural strength and good safety performance to ensure the normal operation of the cooling system and the safety performance of the vehicle.