HVAC box leaking when A/C is running

[1993GMCSierra]

Hi all,

The black HVAC case under the dash to the left of the blower motor steadily drips from time to time when the A/C is running on MAX. It's dripping from the rectangular box just to the left of the blower motor. It's not so bad that it is flooding the carpet, but it's enough that I don't want to have it keep getting wet on a regular basis.

Is it a rubber gasket in there that goes bad, or what? The A/C system does drain, not much when it's cooler, but it does drain.

 

[LordFinesse]

Its the heater core, mine just went out a few weeks ago, fix it soon or you will have a mess in your cab, its a stupid easy fix takes like an hour, incuding going to the parts store, i got mine for 35 bucks from napa. You just take that cover off and disconnect the radiator lines under the hood and replace and reassemble

 

[Dszx13]

One of the easiest to replace lol


Sent from the legion of doom

 

[kidd666]

Easy fix. I did a write up with pics that u can look up. Can't post it off my phone

Sent from my SAMSUNG-SGH-I717 using Tapatalk 2

 

[1997chevydriver]

If it drips ONLY when the A/C is on it's not your heater core. Check to make sure ac drain (under hood on firewall) is not partially blocked.

 

[Half Assed]

I agree. The drain must be plugged.

The dripping underneath is probably from just the lines going into the firewall.

 

[1993GMCSierra]

It's not the heater core, it's leaking water, not coolant. It only leaks when the A/C is running.

I'd tried to wiggle a welding rod around in there, but it didn't come out nasty. Do I have to remove the entire heater box to get to it from the other side? It may well be plugged, but I'm unsure as to how to unplug it.

I can also confirm it is actually leaking from where the bottom mates to the heater box. if there is a seal there, it's not doing it's job.

 

[qukon 95]

no!! you have to remove the blower motor to gain acess to the drain plug and while your in there look at the heater core to see if it's dirty and clean it if needed
it will improve air flow.

 

[BOWTIE_TEXAN]

my truck does the same thing. but it gurgles with the rpm. its not coolant its just water. anyone have any ideas. oh and is there an easy way to get blower motor out this ones a pain in the @$$