The mechanic said that he couln't tell where the coolant leak was coming from. I need to add coolant about every two weeks (500-600 miles). I can't seem to see any noticeable coolant on the ground below the car. Mechanic advised that probably need a new radiator.
Coolant Leak on 2006 BMW 525xi
It may be a great application to try putting in a little "Bars leak" or "Allumiseal" which are both cooling system sealers, just a little may plug the source of your leak. The way an automotive shop would locate the leak is by removing the radiator cap and attaching an adapter that screws on in place of the radiator cap. Something that looks like a bicycle pump with a pressure gauge attached to it is used to "pump up" pressure to simulate pressure generated when the cooling system is at operating temperature, the leak is then found sometimes it is obviously leaking from a coolant hose or cracked housing, failed gasket or water pump, sometimes the engines cooling system needs to be inspected from below or inspected using a mirror and flash light.
I can't seem take off my radiator cap in order to put in Bars Leak. Is there a special way to take off BMW radiator caps? Thanks