Water has a very high specific heat, why does this make it a very good substance for use in
cooling systems of automobiles?

Water has high specific heat capacity so without a high increase in temperature , water can absorb a large amount of heat.

Explanation:

Water is a very good substance for use in cooling system of automobiles because water has a ridiculously high heat capacity specially its volumetric heat capacity.

 water takes  a tremendous energy  to change the temperature of water and and it gives enormous cooling capacity compared to metals like rapidly absorbing heat energy from the engine.

To cool down the car engine water is used. Water has high specific heat capacity so without a high increase in temperature , water can absorb a large amount of heat.

 Water is efficient heat transfer fluid .

Water offers the thermal conductivity advantages of a liquid with high specific heat capacity and evaporative cooling .