To find out how much coolant should be drained and replaced with water to reduce the antifreeze concentration to the recommended level, we can follow these steps:
Step 1: Calculate the initial amount of antifreeze in the radiator.
The radiator has a capacity of 3.6 liters, and it is filled with a solution that is 60% antifreeze. So, the initial amount of antifreeze in the radiator can be calculated as:
Initial antifreeze amount = 3.6 liters * 60% = 2.16 liters
Step 2: Calculate the desired amount of antifreeze for summer driving.
The manufacturer suggests that the optimal cooling is obtained with 50% antifreeze. So, the desired amount of antifreeze for summer driving can be calculated as:
Desired antifreeze amount = 3.6 liters * 50% = 1.8 liters
Step 3: Determine the difference between the initial and desired antifreeze amounts.
Difference = Initial antifreeze amount - Desired antifreeze amount
Difference = 2.16 liters - 1.8 liters = 0.36 liters
Therefore, to reduce the antifreeze concentration to the recommended level, approximately 0.36 liters of coolant should be drained from the radiator and replaced with water.