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A/C Water Leak On Driver's Side Floorboard

I drive a 2000 Saturn LS1. My current problem is that every time I run the A/C for an extended period of time water soaks my driver’s side front floorboard, with a little bit (but not much) making the passenger side floorboard damp. A friend who is a pretty decent mechanic told me my heater core was busted and causing the water leak, so we bypassed the heater core. The next time I ran the A/C for over two hours, the water came back. I’m 90% sure the actual cause of the water leak is my A/C drain being clogged. What can I do to fix it? Also, why does this happen only on long trips?

Just find the little rubber tube coming out the base of he firewall under the hood and blow it out with compressed air or stick something up the tube like a nylon tie strap.

The reason it happens on long trips is b/c the drain is probably only partially clogged. Some water is getting out, just not enough. The AC causes water vapor in the air to turn into liquid water. All the while the AC is on, this is occuring. This water is supposed to drain out as fast as it enters the drain. But the amount of water entering your drain is more than is draining out due to the partial clog, and eventually, on long trips with the AC on, the drain is overflowing.

You ought to be able to unclog the drain yourself, provided you can find it. Then poke it with a stiff wire, or the line from a weed whacker.

Thanks y’all. I’ll stick something up there and see what happens.

@George
Sorry, hit “disagree” accidentally…a stray click, not intended.

I have the same issue in my 2004 sierra my mechanic and oriellys guy said that if it only does it while running a/c its not the heater core and I’ve checked the drain plug and its clear what else could it be

Blow compressed air up the drain hose, it is clogged, even though you don’t think it is. Just had this on my 07 Silverado, same body style as your Sierra.