One day the passenger floor on my 1993 164L was soaking wet. Everyone told me it was the heater core. I bought a brand new one and had it installed. A few weeks later, same thing. I returned it to the mechanic who checked it but he could not find anything that would cause this. the heater core worked fine. What else could cause this? There are no signs of any leaks anywhere inside the vehicle.
I haven't had it happen in the 164 yet, but this happens frequently in
the Milano when leaves and crap clog the drains at the base of the
windshield. The water gets forced into the heating ducts, and finds
its way out onto the passenger floor.