My 2003 530 has had a slight coolant leak that got worse after a cooling system overhaul. It looses about 3-4 ounces every 3-4 weeks. I've looked at all the hose connections, water pump, expansion tank and cannot see any telltale signs of leakage. Never see any visible seepage. Anybody have any suggestions? I wonder if I may have a heater core issue but I never smell coolant nor do I get any telltale residue on the windshield which I've known in other vehicles to indicate a heater core leak.

Any easy way to visually check the heater core without removing the entire dash?

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