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  1. #1

    Default Condenser Box or Heater Core?

    Ok, so I have a leak apparently in one of these two components I believe. I noticed just yesterday that the carpet underneath my passenger side front floor mat is damp and wet. Now typically I would say right away that this is the heater core that has a leak, however it does not smell of anti-freeze and my coolant level isn't low at all. So I started looking under the hood and realized that the evaporator core for the AC is mounted against the firewall, but it looks like the condenser box for the AC is between the firewall and the dash. (which is something new for me since my last two trucks had the condenser box viable and accessible from the engine compartment.

    So, I'm seeking some knowledge from someone that might have an idea of what is leaking. What I'm figuring is that if the condenser is behind the fire wall right behind the evaporator core, then there would not be room for the heater core right there, and that the heater core might be more towards the middle of the firewall. But, I could be wrong. So if anyone has some knowledge of this or has some ideas, please help me out. I'm trying to get an idea before I start opening things up and trying to see where it is coming from.

    2004 Silverado 2500 "Judas"
    Crew Cab and Short Bed
    6.0L Vortec
    Diablo Predator
    True Dual Exhaust: Hooker MaxFlow Mufflers and X-Pipe
    Drop-In K&N Air Filter
    Alpine Stereo System: iDA-x303 Deck, SPS-600 Front and Rear Speakers, KTP-445 Amplifier

    Future Upgrades Include:
    Cosmetic/Other: Spray-In Bed Liner, HID head lights, Leveling Kit
    Performance: Underdrive Pulleys

  2. #2


    Basically the cold coils portion of the A/C (evaporator) through which air flows will cause condensation. This is just like a cold glass of water.

    That water in a vehicle needs somewhere to go. This is through a drain hose at the bottom of the compartment in which the evaporator is housed. And this would drain to the outside.

    So look at the bottom of the firewall for a tube coming out and clear any clogs inside that tube.

    If you are working under the vehicle, don't have your head under the tube when you clear the clog as a lot of water may come pouring out!

    And this is the same as a window air conditioner. There is frequently a tube in the back or you will see water dripping out the back. Newer models use the water to cool the back coils and you will hear water splashing. But this water is from condensation.
    92 GMC Sierra 2500

  3. #3


    Well I checked this hose and ran a piece of wire through it the best I could and didn't find any clog. So I'm not sure if that is where the problem was or not. I noticed that the hose wasn't quite angled all the way down tho so I did re-angle it so that the condensation would drain out better. But I'm not sure if that was really the problem or not. The next few times I drive it though I will check and see if the problem is solved or not.

  4. #4


    Ok. So that seemed to be the problem. I dried the carpet out yesterday afternoon. Then today after driving it around I was gonna see if it was getting wet again and it didn't. So I guess that tube not being properly angled was the problem lol

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