Coolant leak

[78F350]

Originally Posted by LoneWolfGal

... Does that sound like an HVAC issue?

Picture your heater core sitting right behind the battery with coolant flowing through it continually (there is no coolant valve to shut off the heater.) The heater core is in a plastic 'box' with a drain at the bottom. The drain connects to a tube that goes down the front of the right footwell and through the floor near the center to drain under the car.

Here's a HVAC system removed from a 2001. The tubes facing forward are where the heater hoses connect.


You can probably pinch the two hoses off (behind the battery) to diagnose if the heater core is the problem. If they are clamped shut and the leak stops you found the problem. I have had to replace heater cores in an '04 and '99.