Radiator and cooling system hoses have a life expectancy. For V8's it might be 9 years. Its recommended to replace certain hoses BEFORE they start leaking or the plastic connectors deteriorate. Many BMW's have electric water pumps and thermostats that fail. Radiators can leak. Electric cooling fans may not be running to full potential thereby causing poor engine cooling or air conditioning operation. Fan assembly, hoses, radiator, expansion tank, thermostat, water pump inspection and replacement. Leak inspection and system pressure testing. N62 (545i, 550i, 650i, X5) dreaded leaking hidden coolant pipe replacement.
