When running the AC condensation builds up until there is a puddle on my floor.

Dear Car Talk

Dear Car Talk | Nov 01, 2003

Dear Tom and Ray:

I have a 1994 Honda Accord with 125,000 miles. When I run the air conditioning, condensation quickly builds up in the ventilation system and drips water onto the floor mats and feet of both driver and passenger. I'm guessing there is a drain somewhere that is plugged up. Where is the drain, and is it something I can fix myself? My girlfriend refuses to ride in my car until I get the problem fixed. Help me! -- David

RAY: Tell her you paid extra for the optional "foot bath" feature.

TOM: Actually, you're right about the drain being plugged up. When you run the air conditioner, one of its jobs is to remove moisture from the passenger compartment. Normally, that moisture gets condensed and then drips onto the ground underneath the car via a drain. I'm sure you used to notice a small puddle of water under the car when the AC was running.

RAY: And you no longer notice that puddle, do you, David? That's because the drain's plugged up and the water is draining onto your girlfriend's feet instead.

TOM: The evaporator drain is located on the underside of the car, where the firewall meets the floor pan. It looks like a little piece of rubber tubing. And while you CAN attempt to clear it out yourself, I wouldn't recommend it. The evaporator itself holds the refrigerant. If you happen to poke a hole in that with your screwdriver or clothes hanger, it'll cost you several hundred dollars to replace.

RAY: So the preferred tool for the job is compressed air. If you go to any gas station or service shop and ask them to blow out your evaporator drain, they should be able to do it in a few minutes, for minimal cost.

TOM: If you have a regular mechanic you go to, you can even wait until your next oil change and ask him to blow out the drain while he has the car up on the lift. Many places will even do that for regular customers for free.

RAY: But if you decide to wait until your next oil change, at least invest in pairs of his-and-hers Tevas so you can enjoy the "foot bath."

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