# Mildew Odor in AC



## pony_trekker (May 26, 2003)

*Stink*



GM said:


> So what happens when it gets cold outside?[/QUOTE
> 
> I always leave the air on year rond. That's the best way to get rid of fogged windows.
> 
> ...


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## SG1 (Sep 24, 2002)

MysticBlue said:


> This is not a BMW only issue... I've experienced this in half a dozen different cars I've owned over the years. I started turning off ac a few minutes before arriving a long time ago... to dry out the condenser before shutting things down. It usually helps. I also used to occasionally turn ac on, turn fan on full blast and spray Lysol into the air intake. That always cured the problem for awhile. Not sure that would work with the bimmer because of the filter.


I've had bad experiences with using the lysol method. Not only will the mildew smell return after a couple of days, the lysol smell itself was worse than the original mildew smell. Maybe it was a combination of the lexol, new-car, mildew + lysol ordors.. but whatever it was, it was nasty.


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## Plaz (Dec 19, 2001)

FireFly said:


> Oh yeah, forgot to mention, NO car should do this! Let alone one which is in the 30-40k price range. I have never been in another car which had this problem- so what the heck gives here?????


 

I've never had a car that DIDN'T do this, except my CRX.

(It didn't have A/C.)


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## fins1972 (Sep 12, 2003)

I replaced the microfilter and that seemed to do the trick. Found it online for about 20 bucks.


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## ldn (Jan 22, 2003)

vatkens said:


> I'm with BMW of North America, LLC. I've checked with our experts regarding this issue. This is an industry wide problem caused by humid conditions. Moisture that condenses on the evaporator can provide an environment favorable to microorganisms drawn in either from the outside air, or from inside the passenger compartment (particularly from food or pets). This can cause a musty odor, when the air conditioner is first switched ON.
> 
> Using a specially designed tool, your BMW center can chemically clean the evaporator and evaporator box with disinfectant. However, while this can solve the odor problem for an extended period, it is not a permanent fix because the microorganisms can grow again due to the humidity in the air.
> 
> ...


vatkens,
Thank you for taking the time to post. However, I still have to say this is a BMW issue. Right now, there are 5 cars in my family: one 1998 Honda Civic, two 2000 BMW 323i, one 2001 Nissan Maxima, one 2002 Mazda Protege. Guess what, the two BMWs are the only ones that stink with this problem. Before this group of cars, I also had a couple Saab's, Toyota, a couple older BMW's, etc ... I have been in Acura, Audi, and at least a dozen other brands/models. None of them stinks like my two BMW's.
Yes, I do enjoy driving my BMW's. No, the stinky smell does not belong in these cars (or any car, for that matter). I know about the turning-the-AC-off-a-few-minutes-before-arriving "solution" ... but ... is that an appropriate solution that belongs in a fine automobile? I don't think so. Please fix it properly.
BTW ... What can I expect if/when I call 800-831-1117 for "additional question or assistance"? Will I be placed 1st on the list to receive the fix for this problem  ? or someone will tell me to turn off the AC a few minutes before arriving  ?


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## woohoo (May 29, 2003)

vatkens said:


> I'm with BMW of North America, LLC. I've checked with our experts regarding this issue. This is an industry wide problem caused by humid conditions.


My Honda never had this problem. In my Honda, I used the A/C 5-10% of the time (mostly for defogging), now I run the A/C 90% of the time just so I don't choke from the humidity.


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## karrickk (May 5, 2003)

I too have never turned off the AC since i purchased the car and I still get the mildew smell at startup. I tried using the Wurth disinfectant but that only lasts 3 days or so before the smell comes back. When I brought to Weatherford BMW service, all they could tell me was to spray the filter with disinfectant, they mentioned nothing about the option of:

"Using a specially designed tool, your BMW center can chemically clean the evaporator and evaporator box with disinfectant. However, while this can solve the odor problem for an extended period, it is not a permanent fix because the microorganisms can grow again due to the humidity in the air."

Has anyone ever brought their car in to service to have this done successfully?


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## JimONeill (Oct 8, 2003)

karrickk said:


> I too have never turned off the AC since i purchased the car and I still get the mildew smell at startup. I tried using the Wurth disinfectant but that only lasts 3 days or so before the smell comes back. When I brought to Weatherford BMW service, all they could tell me was to spray the filter with disinfectant, they mentioned nothing about the option of:
> 
> "Using a specially designed tool, your BMW center can chemically clean the evaporator and evaporator box with disinfectant. However, while this can solve the odor problem for an extended period, it is not a permanent fix because the microorganisms can grow again due to the humidity in the air."
> 
> Has anyone ever brought their car in to service to have this done successfully?


I ALMOST had that procedure done. I had taken my 2001 325i in three times for the stinky a/c problem. The first two times the dealer changed the microfilter and sprayed some sort of Lysol-like substance into the A/C system. The Lysol smell was overpowering for a few days but the mildew odor did go away for a month or more.

The third time, the service adviser said that he had checked with BMW and was going to use the "specially designed tool." As he described it, it involved pulling back the carpet and drilling through a hole somewhere in the area of the driver's footwell and then washing out the evaportor box with another Lysol-like chemical. But he said that he didn't have the chemical and needed to find it. He said he needed to look at Home Depot or someplace similar (!). He was supposed to call me when he got it to schedule the service but he never did. As it turned out, the lease was up on the car in another month or so anyway, so I never bothered to bug him about it again.

By the way, on that car, I left the A/C on all the time and still got the stink.

On my 2003, I'm trying not to run it all the time just to see if I have a different experience. But not running it seems to cause a lot of window fogging. I really prefer to keep the A/C on all the time regardless of the temperature, as the drying effect is beneficial. But I guess it's the moisture that it extracts from the air that causes the mildew problem.


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## F1Crazy (Dec 11, 2002)

Check out this SIB: Musty odors from A/C system.

I think that we all have to thank RS2 for all these SIBs, :thumbup: !


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## ldn (Jan 22, 2003)

You know ... after running the AC for a while on my other cars, I always see a small puddle of water on the ground. Not on my 2 E46's. I don't recall ever seeing puddle of water under them. Hmm, maybe BMW engineers forgot to implement a drain tube for this?  :dunno: 
Do any of you see any sign of drainage on your E46?


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## Plaz (Dec 19, 2001)

ldn said:


> You know ... after running the AC for a while on my other cars, I always see a small puddle of water on the ground. Not on my 2 E46's. I don't recall ever seeing puddle of water under them. Hmm, maybe BMW engineers forgot to implement a drain tube for this?  :dunno:
> Do any of you see any sign of drainage on your E46?


Yes, always. :dunno:


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## ts330ci (Jul 30, 2003)

This happens to all my vehicles if you have the A/C on after a drive and turn off the car and let it sit for a few hours. When turning the car back on, smell mildew from the vents.
Here's what I do and I don't smell the mildew anymore. A few minutles before getting to destination, turn the A/C off but leave the fans on. This allows most of the moisture in the vents to evaporate from the system. I also keep the fans on low (A/C off) whenever I drive, no smells from vents since doing this.
I've got a variety of vehicle makes and they all get that mildewy (sp?) smell when you first turn the A/C on if you don't allow the vents to air out after the a/c's been on.


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## Galun (Aug 14, 2002)

karrickk said:


> I too have never turned off the AC since i purchased the car and I still get the mildew smell at startup. I tried using the Wurth disinfectant but that only lasts 3 days or so before the smell comes back. When I brought to Weatherford BMW service, all they could tell me was to spray the filter with disinfectant, they mentioned nothing about the option of:
> 
> "Using a specially designed tool, your BMW center can chemically clean the evaporator and evaporator box with disinfectant. However, while this can solve the odor problem for an extended period, it is not a permanent fix because the microorganisms can grow again due to the humidity in the air."
> 
> Has anyone ever brought their car in to service to have this done successfully?


I had this done a couple months ago. No smell so far... although it just starting raining around here.... Oh well. :dunno:


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## gp330 (Sep 2, 2003)

Galun said:


> I had this done a couple months ago. No smell so far... although it just starting raining around here.... Oh well. :dunno:


Where do you spray the Wurth? I took the filter out and cleaned it, but it didn't look or smell bad (car only has 5K miles).

Do you spray the Wurth in the vents behind the filter?

I get the moldy smell also...it's dang humid in the south.


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## Terry Kennedy (Sep 21, 2002)

F1Crazy said:


> Check out this SIB: Musty odors from A/C system.
> 
> I think that we all have to thank RS2 for all these SIBs, :thumbup: !


I performed the procedure myself. On an E46, it isn't any more difficult than replacing the final stage resistor, a common DIY. The cleaning kit pretends to be a final stage resistor for mounting purposes.

See my Air Conditioner de-funkifying thread for info about the kit and cleaner.


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## biggie (May 6, 2004)

had the same problem and when i went in for inspection 2 they changed the air filter and found a couple of dead flies... ever since then hasn't been a problem


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## Terry Kennedy (Sep 21, 2002)

biggie said:


> had the same problem and when i went in for inspection 2 they changed the air filter and found a couple of dead flies... ever since then hasn't been a problem


Yes, that's the first thing to do. But even with a new microfilter and a good vaccuming of the area around the filter, I still had the funky smells, which have gotten a lot worse in the past 4 months or so, so I decided to do the cleaning procedure.


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