Coolant leak

[78F350]

This sounds likely:

Originally Posted by tcoradeschi

...
Is that one of the condensate drains from the heater box? Do you smell coolant inside the car? If so, maybe you are looking at a failed heater core, or something of that nature? ...

[LoneWolfGal]

Originally Posted by 78F350

This sounds likely:

It's below the passenger footwell, sort of, but more toward the middle, under the right side of the center console. I lost a lot of coolant, enough to overheat rather suddenly. Does that sound like an HVAC issue?

[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.

[LoneWolfGal]

Originally Posted by 78F350

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.

[ image ]

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.

I plan to follow your suggestion and pinch off the hoses to confirm the heater core as the problem. In the meantime I've been consulting my Bentley service manual and watching YouTube videos showing how to replace the heater core. Seems fairly straightforward. (I've seen a lot worse, like having to disassemble the entire dash to get to the heater core.) One thing's giving me pause. Seems like most of the folks with heater core leaks report considerable moisture, from dampness to soaking wet, in the interior carpet. The carpet on mine is as dry as a proverbial bone. But pinching the hoses should tell the tale, right?

Thanks for the helpful info.