2007~2015 CX-9 A/C draining direct to passenger footwell

[jase7678]

It’s been a while since my A/C drain got clogged and, unlike last time, I approached the task with confidence and therefore didn’t read the forums before tackling. I recalled reading references to the use of an air compressor but forgot the salient parts about this not being the best route and, if used, to use light pressure (a vacuum being the preferred approach).

I’ve come to own an air compressor since performing this operation the last time and gave the drain pipe several long, high pressure blasts with glee.

This was entirely the incorrect approach and now water drains onto the passenger carpet mere seconds after having the A/C running.

I presume I’ve caused something to become unsituated. Can anybody recommend / point me to info source on how to strip back necessary pieces to remedy the situation please?

Thank you.

 

[jase7678]

Took the afternoon off work today to see if I can fix the problem I created by blasting the A/C drain hose with air pressure.

Looking at the blown up drawing of the A/C Unit it seems I must have dislodged the drain hose. I'm hopeful this is accessible from the passenger footwell.

Does anybody have any experience or hints & tips they could share?

Thank you.

 

[puma]

if it didn't leak when you blasted it, than my guess is it is still clogged. If water runs only with AC on, that means it is still full. Did you do it in the first place in a preventive matter or because you were hearing the water slouch around?In any case, that hose should be behind the carpet on the passenger side but it is just a guess.

 

[jase7678]

if it didn't leak when you blasted it, than my guess is it is still clogged. If water runs only with AC on, that means it is still full. Did you do it in the first place in a preventive matter or because you were hearing the water slouch around?In any case, that hose should be behind the carpet on the passenger side but it is just a guess.

Hi @puma,
I blasted it because it was overflowing in the usual manner of cornering when the drain is blocked. So I blasted it with the air compressor and lots of water ran out onto the driveway as expected. Thing is, not 2 days later my wife comes home and tells me our nephew said he could see water running down the transmission tunnel onto the carpet. I couldn’t believe it. So I fired up the A/C and low and behold water starts running down the transmission tunnel in passenger footwell while the car is stationary on the driveway so I figure that, as soon as moisture comes off the evap, it’s just running into the foot well as opposed to collecting until there’s a good amount of water and coming out under cornering.

All assumption by the way because the parts diagram doesn’t make it easy to picture exactly what it looks like in there and where, when it’s blocked, water sits - presumably for a long time but maybe it starts overflowing as soon as it’s blocked??? I just imagined there was some sort of unintentional reservoir based on the amount of water that runs into the fan when it’s blocked.
Heading out to car now.

 

[jase7678]

I’ll try hooking the shop vac up to the drain tube before starting any dismantling just in case the problem is the original blockage falling back into place.

 

[jase7678]

Ok, status update. Put shop vac with reducer down to beach inflatable pump hose and shoved it into the drain. No water evacuated.
Removed glove box and panel below this and got some good video of the inner workings. Spotted the evaporator which is probably around the same height as the glove box - I’d expected it be somewhat closer to the floor. Could not spy any tubing.

Ran engine and A/C keeping any eye inside the footwell and below the car. For a long time no moisture anywhere. And then dripping from the drain pipe!!!!

At this point will consider it fixed and put it down to Heck Knows What Was Going On!

Fingers crossed it behaves itself.

Will upload some stills from the video later to share the inner gubbins.

Have to say I got a kick out of seeing the lid over the cabin air filter retract when operating recirc mode! #ImABigKid

 

[rowlands57]

If the issue comes back you could try to snake a thin weed trimmer cord up the drain from below. If that shows up inside the 'box' then you should be good. If the cord shows up elsewhere that would be the point where the disconnect happened.

 

[jase7678]

If the issue comes back you could try to snake a thin weed trimmer cord up the drain from below. If that shows up inside the 'box' then you should be good. If the cord shows up elsewhere that would be the point where the disconnect happened.

That’s such a smart idea! I’ll definitely do that. I’ll see if I can befriend a proctologist in the meantime and borrow their camera

 

[jase7678]

Came back on Friday and with a vengeance today: water was pouring off the trim below the glove box. Absolutely insane. And of course I’m away from home with zero tools. I had a 12” cable tie and parked the car on a small knoll so I could slide underneath. The cable tie hit a hard stop 3/4 of the way. Could have just been a 90 degree bend or similar. I purchased some weed trimmer cord but then the heavens opened. I can’t believe the evaporator creates so much moisture but it’s in the 90s and very humid here.

While researching this I found the car has a separate evaporator for the rear. If that’s true it would be great if you could engage the A/C independently in the rear. Then I could get some relief because opening the windows isn’t doing it.

 

[TheMAN]

there's no reason this would've happened except crap building up on the evaporator core... so, somehow either the cabin filter was never changed/changed often enough, the car was ran without it, or it had crappy aftermarket cabin filters where unfiltered air got around the deformed filter

oh and if you use the "fresh air mode" a lot, a lot more crap easily gets in from the outside, especially if you always park your car outside and never set the air back to "recirculate" when you park it

 

[jase7678]

there's no reason this would've happened except crap building up on the evaporator core... so, somehow either the cabin filter was never changed/changed often enough, the car was ran without it, or it had crappy aftermarket cabin filters where unfiltered air got around the deformed filter

oh and if you use the "fresh air mode" a lot, a lot more crap easily gets in from the outside, especially if you always park your car outside and never set the air back to "recirculate" when you park it

If the state of the cabin air filter can cause this then that’s probably what’s going on.

This was last changed by Mazda a couple of years ago but it was bad. I’d never attempted to look at it myself but it does need replacing and I will do so ASAP.

And I use fresh air mode 99.9% of the time. The only time I don’t is when following something smelly.

I want to be able to follow the path of the water from evaporator to top of fan.

 

[GonzoSTL]

If the state of the cabin air filter can cause this then that’s probably what’s going on.

This was last changed by Mazda a couple of years ago but it was bad. I’d never attempted to look at it myself but it does need replacing and I will do so ASAP.

And I use fresh air mode 99.9% of the time. The only time I don’t is when following something smelly.

I want to be able to follow the path of the water from evaporator to top of fan.

I have this exact same issue. Our 2008 CX-9 was parked near the woods for an extended period—later I found rodent nests behind the glove box and inside the cabin air filter passage. I’m guessing some of that filth got to the evaporator core.? I tried three times to find the drain nipple outside on the passenger side firewall, third time was a charm, I think. However, tried probing dried air pressure tried shop vac nothing dislodged anything. No water ever came out from under the car.
Today I peeled back the carpet and removed the trim beside the accelerator pedal and found the drain tube that goes through the firewall (I understand that’s the inboard end of the same drain tube). No water was apparent inside that black tube, so the clog must be way up earlier in the system? If you take it to an air conditioning repair shop for automobiles, what would they do to clear a clog that doesn’t respond to the typical approach of probing, compressed air, Shop Vac. Exactly what do they disassemble and how do they get to it, and how do they clear a solidified clog on the interior of a housing or core or whatever it is?

 

[jase7678]

I have this exact same issue. Our 2008 CX-9 was parked near the woods for an extended period—later I found rodent nests behind the glove box and inside the cabin air filter passage. I’m guessing some of that filth got to the evaporator core.? I tried three times to find the drain nipple outside on the passenger side firewall, third time was a charm, I think. However, tried probing dried air pressure tried shop vac nothing dislodged anything. No water ever came out from under the car.
Today I peeled back the carpet and removed the trim beside the accelerator pedal and found the drain tube that goes through the firewall (I understand that’s the inboard end of the same drain tube). No water was apparent inside that black tube, so the clog must be way up earlier in the system? If you take it to an air conditioning repair shop for automobiles, what would they do to clear a clog that doesn’t respond to the typical approach of probing, compressed air, Shop Vac. Exactly what do they disassemble and how do they get to it, and how do they clear a solidified clog on the interior of a housing or core or whatever it is?

I never thought to strip things down on the driver side footwell but it makes sense since the outlet of the hose is on the driver’s side of the transmission tunnel.

Did you remove the plastic trim at the transmission tunnel so you could see the bottom of the box containing the evaporator? I couldn’t figure out how to remove that so did everything peering over the top of that [from the passenger side].

If you can see where the drain hose goes into that box can you remove it so you can see what’s clogging it? Somebody recommended pushing weed-eater string up into the tube from underneath the car but I could only get it so far before it hit a 90 degree bend or lip or similar. So I’m not sure how an HVAC tech would do it.

I found a way to get access into the main box and could feel the fins on the evaporator coil with my finger tips. This was either from where the cabin filter is but could have been reaching up with the fan removed. Anyway, I hopefully remedied my problem by simultaneously sucking from that location with a narrower tube on the end of the shop vac while blasting the drain tube under the car with the air compressor: the theory was something like those game show machines where they blow money around and the contestant needs to catch it only in my case it was leaves & acorns lol.