The water pump is the heart of the cooling system. Even though it is uncommon, it is also attainable to mis-route a serpentine belt on particular vehicles. Such a mistake can trigger the water pump to rotate backwards and overheat the engine. Ideal is to always refer to the routing diagram when replacing a serpentine belt.
Thank you for asking about your Lexus. Do you happen to know what caused the radiator to start leaking? Was the cooling technique creating up a lot of pressure? You mentioned the vehicle was operating rough, also. Have you noticed any troubles with engine power? Please speak to our technical assistance so that we can get a small better understanding of the vehicle's situation and be able to make any proper suggestions.