2004 Ford Fiesta Repair Question
Ford Fiesta Coolant Problem
Air bubbles in the coolant reservoir are usually from a leaking head gasket. The clue is the coolant won't be hot or steaming. A leak can be verified with a "sniffer" test. Air is drawn from the radiator through a glass cylinder with two chambers partially-filled with a special dark blue liquid. If combustion gases are present, the liquid will turn bright yellow.
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