Hi, new to forums here, so howdy!
Working on a 06 Buick lacrosse which I believe is the same car as 8th gen Impala.
Sooo, just replaced heater core,(not fun!!) Now after running ac for awhile I'm getting a puddle of water on the passenger side floor!
Not sure what I missed or messed with as far as evaporator goes but obviously something?
Anyone who might have experience with these stupid cars HVAC system with any thoughts would be greatly appreciated!
I'm just probably afraid I'm going to have to pull that POS back apart, LOL!!
THANKS!

 

When you replaced the CC box, did you have a hang-up with the drain hose that goes way down at the very bottom of the firewall? Nothing stupid about it. All HVAC systems, like the one on your home have to drain the condensate water somewhere. It is how they are designed.

 

Thanks for responding, Honestly I didn't even see or notice the drain hose.
Is it behind, below the heater core or??
Pretty frustrating because I have yet to even see a decent picture of this area on the web or anywhere else.
I basically just went off horrible black and white sketches/directions I found on one of those "fix-it" web ads, sure wish I could find a good write up with pics or video on this.
On a side note I'd like to strangle the engineer who designed that box with the screw's AND plastic welds!!
Thanks again for any help!

 

Dont beat yourself over the head. Working on the climate control box is complicated on newer vehicles. That said there should be a rubber drain almost at the floorboard that allows the water condensate from your A/C evaporator to allow that water to drip on the ground, as you will see on other vehicles. It might, and I use that word loosely, be possible to install one from the very lower firewall to the ground.

You will need to get under your vehicle to attain the situation of the water drain hose from the climate control box. It's about 3/4 of an inch or so. If you can verify that it's not there it MAY be possible to install one from outside the vehicle, but I cannot guarantee this at all, whatsoever.

If I were to try this I'd run something flexible in there to find it. Normally these drains are just a hose with a groove that goes into the CC box and then outside the firewall. I don't know if one can be attached from the firewall outlet. That is not how they were designed to do.

Perhaps if you loosened up the CC box you could find the drain and pull it out, but IMO that may not work at all. It's best to ascertain the matter by finding the drain hole. Perhaps it could have been pinched for some reason, but you won't know until you check it out.

 

Thanks again for the help, yeah I can see a little 1/4 hose on the outside, underneath the car, where it's coming from, God only knows! It's obscured by other parts, insulation, etc. and can't physically reach it or see where it's coming out.
I was able to blow some air into and can hear it going inside.
I guess it could have been partially pinched or something, just wish I knew were that SOB was INSIDE the car!
Just going to have to disect until I figure out how it drains 😭🤬

 

If you don't run the A/C, at all nothing should come out of the drain hose. It's only there to drain the water from the A/C evaporator, not the heater core at all. I'm curious as these drain hoses usual are at least 1/2" inch in size or more. The only thing that should be coming out is pure water, off the A/C evaporator. If it's engine coolant, then you have a heater core leak, which is why they tend to be larger in size.

 

Well, I think I figured it out, after pulling the dash cover off, etc.. and removing the heater core covers I found it's leaking from one of those STUPID plastic welds I had to split open in the main evap box, (the big one that doesn't come out), I've been in the auto repair trade for 30 year's (retired) and I swear to God this thing has got to be one the top five dumbest designs I've ever seen!!!
Guess I'll epoxy it up and see what happens.
Thanks again!

 

I'm glad you found the leak. They just don't make things like they used to do.