Hi Aling Osang,
When coolant in the radiator is depleting together with the recovery tank, there must be a leak in the system. Some leaks are minimal and would not be easy to detect. Get a pressure test done to locate the source.
If the recovery tank is not drying out but instead overflowing, either the radiator cap is bad or the head gasket has failed.
Wednesday, September 1st, 2010 AT 12:56 PM