2002 gramd marquis
I'm not sure where the heater core is in that one but if it was leaking you would smell a sweet smell in the cabin, and would have fog up on the inside of the windshield when on defrost. If it is just water, then a seal either around the door, windshield, or heater duct work is bad.
Search Mercury Grand Marquis Questions
Mercury Grand Marquis Experts
Related Models For Sale