Mercedes-Benz CLS63 AMG persistent coolant leak despite recent water pump and hose replacement on Mercedes-Benz CLS63 AMG

Some Mercedes-Benz CLS63 AMG owners report experiencing persistent coolant leaks even after recent water pump and hose replacements. These leaks may be attributed to loose hose connections that require re-inspection to ensure they are securely fastened. Additionally, issues with the radiator, such as damage or breaks, could be the source of the leak and may necessitate further inspection or replacement. Some owners also find that despite having a new water pump installed, there could be installation issues or defects with the new pump contributing to the ongoing leak. To diagnose the problem, some owners recommend checking the coolant reservoir for cracks or stains and monitoring coolant levels to prevent overheating. Furthermore, ensuring the correct coolant mixture is used—ideally a 40/60 to 50/50 mix of genuine Mercedes or Zerox-G-05 coolant with purified water—is crucial to avoid system corrosion. If the leak persists despite these efforts, it is advisable for owners to seek assistance from a qualified mechanic or dealership for a thorough inspection.