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Stop the stank before it starts.

166K views 126 replies 59 participants last post by  HondaBc101 
#1 ·
With warmer weather approaching, I thought I’d write an article concerning a recurring problem many experience when using their car’s air conditioning; that’s right, I’m talking about the well known “sock” smell that comes from your vents when you turn the system on. Your smell may vary…it may smell like urine, cheese, body odor, or worse. Whatever the smell, it’s awful and embarrassing. :puke:

Since our cars are equipped with cabin filters, a lot of people will recommend a filter change when the smell occurs. Other helpful souls will recommend spraying Lysol or some other spray into the air intake. Some will suggest checking for a clogged drain hose. Sadly, none of these approaches will fix the problem. They may mask or temporarily reduce the smell, but they don’t directly address its source—bacteria and mold that has grown on the evaporator and the evaporator case.

The evaporator evaporates (duh) moisture from the outside air during the cooling process. The resulting condensation drains onto the ground when the system is on--hence the water puddles you find under your car during the summer. When the system is turned off, some moisture remains on the evaporator and case and the moist, dark environment provides the perfect breeding ground for bacteria and mold—the REAL source of the foul odor.

Obviously, the mold and bacteria need to be removed to get rid of the raunchy smell. You can pay a mechanic a few hundred bucks to “treat” your system or you can do it yourself, know it was actually done (and done right) and save money and time. DIY treatment generally involves spraying a foaming anti-bacterial cleaner onto the evaporator. The foam saturates the evaporator and case, then turns to liquid and trickles back down the drain tube. Many of the cleaners available come with a long flexible tube to facilitate reaching the evaporator without having to disassemble anything. There are many products available and most cost less than $20 per can. Here is a short list of ones I am familiar with; you may find others:

1Z einszett Klima-Cleaner : http://www.superiorcarcare.net/einszett-klima-cleaner.html

Interdynamics Evaporator Odor Eliminator: http://www.oreillyauto.com/site/c/detail/IDN0/OE1.oap?pt=N1787&ppt=C0050

Kool-it Evaporator Cleaner: http://www.autobarn.net/lubegard-heater-core-foam-cleaner.html

BG Frigi-Clean: http://cgi.ebay.com/ebaymotors/BG-F...542QQitemZ120573060418QQptZRaceQ5fCarQ5fParts

FJC 5914 Foaming Evaporator Cleaner: http://www.amazon.com/FJC-5914-Foaming-Evaporator-Cleaner/dp/B002EAKX88

Foaming Evaporator Cleaner: http://www.nostalgicairparts.com/ai...-evaporator-cleaner-714.php?source=googlebase

Note: The aforementioned items ARE NOT air fresheners, they are evaporator cleaners. Many of them will at first provide a pleasant scent which will soon disappear but by no means does this indicate that the products have stopped working. If you want a long term air freshner, buy something other than the above. If you want a clean evaporator that leads to odor-free air, then these products (among others) will work for you.

Although the instructions will vary slightly depending on the product you choose, I’ve had great success treating systems by spraying the cleaner up the evaporator drain hose (using the provided flexible tubing) from underneath the car, directly into the evaporator case. Generally speaking, two treatments per year will keep the funk away.

After you have treated your car, there are some steps that can be taken to help keep the odor from returning:

1. Turn the A/C off (but keep the blower on) about a mile from my destination to help dry some of the condensation and reduce the moisture level on the evaporator coils and case.

2. Minimize the use of the “recirculation” feature, because it allows for the recirculation of mold spores and makes the smell return sooner.

I know this process may sound overly simple, but it really is very easy.

There’s nothing worse than getting into a clean, well-maintained, good-looking car and being blasted by the eye-watering stench of funky feet. So be proactive and stop the stank before it starts.

Side note: Since I started using this process, I no longer experience the "sneezing fits" that I used to have at the beginning of my morning commute. My non-expert guess is that lower mold levels lead to less sneezing.

I hope you found this article helpful, perhaps even sticky-worthy.

Disclaimer: follow product directions and if in doubt, consult a qualified technician.
 
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#5 ·
...Of course, I also turn the A/C off (but keep the blower on) about a mile from my destination to help dry some of the condensation and reduce the moisture level on the evaporator coils and case. I also minimize the use of the “recirculation” feature...
I think this is a good write up!

Knock on wood...I have had good luck in the past with other vehicles & I have not experienced the smells from the A/C system.

I have not used any products in the past, but use both methods mentioned above & have not had any of the nasty smells.
 
#6 ·
and i thought i was the only one with this problem....good to know there are others out there.

for me, it's the smell of feet. and not the pleasant just-out-of-the-shower feet....it's the i-just-played-ball-for-3-hours-with-day-old-socks feet.

Is there a picture-by-picture/video process on how to use this?
 
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#7 ·
First of all, this problem is extremely common. However, lots of people just settle for air fresheners and hope for the best. They never really address the source of the odor. It's akin to not showering and relying on lots of cologne to hide the ass-kicking body odor.

I don't have pics. Frankly, you can go the super-simple route of fully inserting the tube into the center vents and spraying. The slightly more difficult way (my preferred method) is to discover where your a/c drain hose is (by running the a/c and watching for the drip) and inserting the hose as far into the drain has as possible and spraying. Really, there is no disassembly, no tools, and very little mechanical aptitude required. You can probably do it with ease. All the products I mentioned come with clear, easy to comprehend instructions.
 
#11 ·
You're welcome and good on you. With the 1Z, I usually spray it up the evaporator drain. Stick the 1Z hose up the drain hose as far as you can and rotate it to get max coverage. Shake the can well and DO NOT invert it. Follow the instructions. You're well on your way to stopping the stank before it starts. :cool:
 
#17 ·
Yukfoo:

No problems with the Klima-Cleaner application. About 2/3 of the product applicator tube was inserted into the condensate drain hose. Most of the can was sprayed into the drain hose, but some was sprayed down the center vents too.

The drain hose on my car has a large inside diameter. Eventually the foam started coming out the drain hose instead of entering the evaporator chamber, so I lightly pinched the drain hose closed at the end, with my fingers.

This application was a preventative measure for this car. But the citrus scent is nice. No doubt it won't last that long.

Added bonus: Now the car gets 4.2 mpg better gas mileage and shifts smoother too. :thmsup:
 
#19 ·
Since I started keeping my evaporator clean, I've noticed FAR less sneezing, runny noses, and red eyes. I used to ehbibit these symptoms EVERY morning about 3 minutes into my AM commute. It was downright predictable. Therefore I have decided that an evap cleaning will be part of scheduled maintenance. It will be done every time I change my oil filter during regular maintence, smell or no smell.

It's now less about the stank and more about my own well being. And there you have it.
 
#21 ·
If you need a visual of the science project growing in your evaporator case, here's one. This is the lower evap case from a 2008 Mazda 6. This is part of what causes the odor and cause mold to be blown right up your nose. This gunk grows on your evap too, which stinks AND limits cooling ability. You need to kill it with one of the methods discussed above. You can see the drain tube on the right side of the case.
 

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#24 ·
Here's a generic diagram of a car's system.

As you can see from the location of the filter, Lysol or other chemicals sprayed into the air intake from outside are largely captured by the cabin filter. Only a tiny amount of Lysol gets past the filter to the evaporator and case, where the odor is coming from. That's why that the Lysol treatment and/or filter change has only a short term impact on the sock smell.

The one thing that's missing from this diagram is the evaporator case drain tube, which would be at the botton of the evap case. As I said earlier, I spray the anti-bacterial foam up the drain and let it entirely fill the case.
 

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#28 ·
Looking at the picture in post #24, I should get always the bad smell from the vent since air always passes across the evaporator that has mold.
But that didn't seem to be the case in my car.

There is no bad smell if I turn on the fan (AC on or off) that's already in recirculated mode.
The bad smell comes out of the vent if I turn on the fan (AC on or off) that's started in fresh air mode. If I quickly switch to recirculated mode, the bad smell stops.


Does it make sense to you ? Why did the smell comes out in fresh air mode ?
 
#25 ·
Thanks for sharing! I will try to find an evap cleaner locally tomorrow. My A/C makes car smell musty and it is indeed emberrasing. Will check for clog on evap drain hose and hopefully Advance or PepBoys has this on their shelves.
 
#27 ·
Got this stuff called Kool-IT 96030 Evaporator & Heater Foam Cleaner at NAPA for $13.59. Hose didn't want to go all the way in from the bottom so I got the hose from the inside under the carpet. Released it all and blew on the hose to make sure it's all in, waited for 15 minutes, then ran a/c on Low for 5 mins as directed. Also replaced the cabin filter and air coming out of vents is nice and brisk now. =)
 
#30 ·
Yukfoo,

I re-read my post and it seems a bit confusing so let me re-state the problem, hopefully it will be clearer.

Here is sequence A that always produces moldy smell.
1) Turn on the fan
2) Select fresh air mode (AC is off)
3) Short time later, a moldy smell comes out of the vent.
4) Select recirculated mode and 10-15 seconds later the moldy smell stops.

Here is sequence B that never produces moldy smell.
1) Turn on the fan
2) Select recirculated mode. AC is off.
3) Air smells normal. No moldy smell comes out of the vent at all.

The commonality between sequence A and B is that if I select recirculated mode, there was no moldy smell from the vent.
Maybe there's some mold between the fresh air intake and the blower fan.

If all air passes across the moldy evap, then the moldy smell will come out of the vent regardless of fresh air mode or recirculated mode.

I was thinking of spraying the Kool-It Evap cleaner up the evap drain hose, but I have not done so because I was not sure of the source of the smell.

I bought the car used and the bad smell has been there since I brought it home (18 months ago). Does a dead rodent still smell bad after 18 months ?

If there some mold between the fresh air intake and the blower, any suggest on how would I kill the mold ?
 
#31 ·
Yukfoo,

I re-read my post and it seems a bit confusing so let me re-state the problem, hopefully it will be clearer.

Here is sequence A that always produces moldy smell.
1) Turn on the fan
2) Select fresh air mode (AC is off)
3) Short time later, a moldy smell comes out of the vent.
4) Select recirculated mode and 10-15 seconds later the moldy smell stops.

Here is sequence B that never produces moldy smell.
1) Turn on the fan
2) Select recirculated mode. AC is off.
3) Air smells normal. No moldy smell comes out of the vent at all.

The commonality between sequence A and B is that if I select recirculated mode, there was no moldy smell from the vent.
Maybe there's some mold between the fresh air intake and the blower fan.

Ah, that's a bit clearer.

Sequence "A" has me stumped. Generally speaking, the environment outside the evap case is too harsh for bacteria to thrive so I doubt there's any between the intake and blower.

Are you certain the A/C is off at the beginning of sequence A? I mean, does the display read "AC OFF"? If not, then it's ON, even if it doesn't read "A/C ON". Just asking because sequence A (plus AC ON) is usually when the odor occurs.

I would still go ahead and foam the evap. At least you will have eliminated it as a possible source. Who knows, the smell might even go away.
 
#32 ·
Yukon,

You may be right. I do recall the smell occurs when AC goes from off to on.
I will look into spraying foam into the evap case just to eliminate one source.

Thanks for the explanations.

[
 
#34 ·
I appreciate this post! I was always curious as to what that funky smell was coming out of my vents when I turn my A/C on. Glad to know its not me! Some 1Z Klima-Cleaner has been ordered as it seems to have gotten the most praise on this thread. I will make sure to let everyone know how well it works once I get it! Thanks again!
 
#37 ·
Excellent question!

1Z is a great product but there's no clear guidance on how much to use, not even on the company's website.

Since this is your first application, I recommend using the whole can since the can isn't that large to begin with. As you know, I recommend spraying all of it into the evap drain hose and I like to give it a good old-fashioned flush. However, a friend of mine sprays half up the hose and half into the center vents inside the car. I don't think you can go wrong by using "too much" though.

After application, remember to always turn your a/c off a minute before you reach your destination and turn the fan on HIGH. This will blow large quantities of water off your evap and minimize the amount off moisture left to feed the mold.

Good luck.
 
#40 ·
@txn,

You have probably used up your can of Kool-IT but replace the cabin filter while you're at it.. Maybe something is sitting on it that collects smell and when you turn system on it releases a concentrated amount of odor.
 
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