Anybody fixed a RECURRING A/C drain clog?

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Former owner of a 2010 CX-9 GT
I've seen the threads on clearing the A/C condensate drain with compressed air or a vacuum cleaner. I've now done this 3 times, each time a lot of water gushes out, things are good for a week or so... then the clog comes back. This would be a minor annoyance, except the last time the drain clogged, water got into my blower motor and killed it (BTW Mazda wants ~$400 for this part). I bought a new (aftermarket) blower unit, which took a week to get here. I just installed it, ran the A/C for a while, and no water is coming out the bottom of the car - the drain is clogged again.

I dug into the center console and removed the hose that connects the bottom of the HVAC unit to the drain grommet on the bottom of the car. The hose itself is clean as a whistle, so the clog appears to be in the actual HVAC unit. The problem with this is that getting that out requires the removal of the dashboard, which is not something I really want to contemplate right now.

So the question is, has anyone had this recurring issue? If so, did you ever fix it? I've owned this car since it was new, but I'm at the point now where trading in the vehicle is becoming an attractive option....
 
I've seen the threads on clearing the A/C condensate drain with compressed air or a vacuum cleaner. I've now done this 3 times, each time a lot of water gushes out, things are good for a week or so... then the clog comes back. This would be a minor annoyance, except the last time the drain clogged, water got into my blower motor and killed it (BTW Mazda wants ~$400 for this part). I bought a new (aftermarket) blower unit, which took a week to get here. I just installed it, ran the A/C for a while, and no water is coming out the bottom of the car - the drain is clogged again.

I dug into the center console and removed the hose that connects the bottom of the HVAC unit to the drain grommet on the bottom of the car. The hose itself is clean as a whistle, so the clog appears to be in the actual HVAC unit. The problem with this is that getting that out requires the removal of the dashboard, which is not something I really want to contemplate right now.

So the question is, has anyone had this recurring issue? If so, did you ever fix it? I've owned this car since it was new, but I'm at the point now where trading in the vehicle is becoming an attractive option....

Hello jal142,

I had the same problem as you, I used the compressed air in a can method and that always got the clogged water out but it would get clogged again within a week.

My theory was that the burst of air basically forced the obstruction back into the water and allowed the water to drain but once the water drained the obstruction just settled back into the drain hole again and basically clogged the drain line again. So I came up with this method below and it seemed to work, haven't had a clogged drain since.
See if this will work for you:

Step 1.

Confirm you indeed have a clogged AC drain line. Tell tale sign is wet passenger footwell and sloshing sound when taking hard turns.
The sloshing sound is the fan blades hitting the clogged condensation water. DO NOT IGNORE THIS, two things may happen
a) if not fixed, the blower motor will short and die b) if water hits the ECU, it will get fried and expensive to fix


Step 2.

Jack up front driver side to get ground clearance to get under the vehicle.


Step 3.

Locate the clogged white AC condensate drain it's under near the driver seat in the vertical wall of doghouse,
you'll have to bend back the aluminum heat shield:






Step 4.

Get yourself a cheap wet vac, micro hose attachment kit. and butyl rubber seal :



https://www.amazon.com/dp/ (commissions earned)



https://www.amazon.com/dp/ (commissions earned)


https://www.amazon.com/dp/ (commissions earned)




Step 5.

Stick the micro hose into the CX-9 white drain pipe and wrap the butyl sealant all around, make sure the seal is fully tight all around like you see in my pictures:








Step 6.

Turn on the wet vac and let her rip and suck out all the junk. I was able to suck out what appeared to be a stupid acorn shell, it was broken to small pieces due to the weight of the clogged water, the vacuum seal and the power of the wet vac. Note, the micro-hose has some small vents at the wet vac hose adapter location, that reduces the suction power, just cover the vents with your hands to increase the suction power. It's hard to explain, you'll understand when you see it. you can hear the hissing sound from the vents.




NOTE: this will only work if the drain is clogged !! if you don't have a clogged AC, the above procedure will not work.
you need the weight of the clogged water to create a completely sealed and closed vacuum to forcefully break up the obstruction and suction out the junk.

I can't guarantee this will work for you because I don't know what kind of obstruction you have but give it a shot. Obviously, if the obstruction is a small rock, this won't work and unfortunately that would mean dis-assembly of the evaporator section to get to the obstruction. Anyway, hope this was helpful and saves you some money.

I'm one of those people that like to stick with a car once I figure out their quirks and nuances. Every car has their issues, but once you figure them out and know how to fix 'em , it's a great feeling to stick it to dealers when they try to rip you off and you know how to fix the issues like the CX-9 transfer case and clogged AC drain. That's why new cars are nice but once things go wrong, it's a new learning curve and have to figure them out or get ripped off by the dealer.
 
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This has been a recurring problem for me but not as often. Probably about once a year. I bring it my local garage and they drain it. They've had to dry out the blower motor a couple times too. I have a feeling that blowing it out with compressed air may clear the drain temporarily but doesn't remove all the material that caused the clog in the first place. Once it all settles, you end up clogged again. I'd suggest something like the avidien's reply where you're actually getting all the material out. I was also told not to park the car under trees but that's not an option for me.
 
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