Smell of mildew after A/C is on

[dinan e39]

The cooling system smells kinda funny after i turn off the a/c and run the vent system. i've sprayed lysol in the intakes of the system and that only works for a short time. any other ideas? thanks.

[pegglegg007]

The cooling system smells kinda funny after i turn off the a/c and run the vent system. i've sprayed lysol in the intakes of the system and that only works for a short time. any other ideas? thanks.

diddo... same thing happens with mine. '97 528i

[bimmerfiver]

Lysol the intake vent.
Get an ozone killer thingy from Bav Auto.
Run the system as below tips...see the links
Get a hot girlfriend who smells sweet too...\
A friend swears by his car 12 volt ionizer:

http://cgi.ebay.com/ebaymotors/BELL-...QQcmdZViewItem


http://autorepair.about.com/cs/heati.../aa071601a.htm

David Ta wrote: I am convinced the evaporator design having horizontal fins is the root cause of the AC musty/stench smell on first startup, which will fade out in a good few minutes. ... So, the real cure is to install an OEM evaporator having vertical fins to drain off the condensation, IF there is such one in the aftermarket for any model having this AC smell problem. Or you can modify your car to allow water shedding off easily. An old colleague in the office confirmed that he got this problem with all his recent cars, including Chevy, Ford, Chrysler. Every year, he mixes water and baking soda and poured it into the drain area next to the firewall, rinsing it later with a water hose.
Another option: dry up the evaporator, after every AC use, or at least daily before turning off the ignition, by simply turning up the temperature to full hot, at maximum speed, while selecting "Front Defrost" for a few minutes. You may not like this inconvenience, but comparing to that when a new evaporator is required, and the evap is out of warranty, plus the musty smell every time the "Front Defrost" is selected, I think the inconvenience is justified. (Defrost activates the air conditioner compressor on most cars). This seemed to work for me.

http://www.allpar.com/fix/acsmell.html

http://209.85.165.104/search?q=cache...lnk&cd=1&gl=us

[bimmerfiver]

I've been too lazy to do this myself, my a/c smelled like crap for the first 30 seconds. I did install new cabin filters and you probably should too (they call for change every 10K miles or once a year etc).

I just removed my filters, cranked up the Defroster to max, could feel the air getting sucked down the intakes and sprayed some Lysol down there.

[328iThizz]

change the cabin ait filters?

[bimmerfiver]

Here it is, bmwtips...'Tips & Tricks' then see 'Maitenance' then 'Foul Smell A/C'....here:


http://www.bmwtips.com/

[rocketwagon]

I have the same issue after I turn off the A/C system. Good info here, thanks for the post/research!

[jda2000]

the lysol trick will work, ONLY if you continue with monthly sprays to keep the mold/mildew growth under control.

Also, turn the AC off a couple of minutes before you arrive at your destination and the fan on. The fan will dry out the evaporator and prevent overgrowth of mold/mildew.

[RonaldH]

1999 528i

Interesting post, as I was about to do a similar one.

My AC Compressor, drier and expansion valve (but not the evaporator) were just replaced with a rebuilt (Discount AC Autoparts - Meridian brand) AC unit.

Prior, my AC had "The Smell." Now, it is a clean as fresh air. See my previous post. The old Denso Compressor destroyed itself in 5 years. It was just replaced at 87,000 miles.

Other clues:
Before: Electric fan (CPU-controlled version) used to run slower than now. Now it goes to jet-engine thrust on hot days.
Before: Rarely saw any condensate dripping under the car. Now copious amounts pouring out from the 2 discharge tubes.
Before: I always was unimpressed with my AC's performance. Now it's perfect.

Best,
RonH

[chiefwej]

When the car is shut off the air intake to the AC shuts. With the cabin filters acting as a lid and no air getting into the system all the moisture is trapped. This creates a nice hot moist place, just like those socks closed up in the gym locker, and that's just what it smells like.

The only posting I have seen that claimed to have completely defeated the problem, wired the damper door on the system, so that it would not close completely, thus allowing it to dry out. Otherwise you must let the system run w/o AC for several min before each shut down. PITA. Forget just once and it is back. BMW suggests turn of AC a few min before you arrive at your destination. In Tucson, when it's 105 (like today) I would die!

[540i6sport]

the lysol trick will work, ONLY if you continue with monthly sprays to keep the mold/mildew growth under control.

Also, turn the AC off a couple of minutes before you arrive at your destination and the fan on. The fan will dry out the evaporator and prevent overgrowth of mold/mildew.

That's exactly what I've heard, too. Good call.

[Palantirion]

I used to have that problem until I stopped running the recirc on Auto or On. Since then no smell.

[reelizmpro]

Anyone try putting some sort of stationary air sanitizer/deodorizer/ionizer inside the microfilter air ducts to keep this problem under control? Seems to me, this would be the way to go in the long run. I've been spraying lysol in there for the past few days and it seems to be working. I sprayed a whole bunch in there last night and let it sit overnight.

[Palantirion]

Anyone try putting some sort of stationary air sanitizer/deodorizer/ionizer inside the microfilter air ducts to keep this problem under control? Seems to me, this would be the way to go in the long run. I've been spraying lysol in there for the past few days and it seems to be working. I sprayed a whole bunch in there last night and let it sit overnight.

-The problem is in the recirculating of the air and the moisture it contains. That's what causes the mold that then causes the smell. If you just run with the recirc off 1/2 the time or more the mold will not return.

[tmoody]

i turn the a/c off a few minutes before i get where i'm going. running the normal air through the vents helps get rid of the condensation that causes the smell.

[reelizmpro]

Thanks for the info, I hardly ever use the recirculation anyway. I just picked up the car about a week ago so I guess it's just a matter of time now.

[CaptnGeetch]

recirc is for fags
























j/k

[chiefwej]

I have tried leaving my recirc and auto in the off position. I have had the dealer cut a opening into the condenser and disinfect it with a pressurized spray. Still stinks, unless I run it for several min w/ AC off every time I stop. A real PIA when you running several errands. I am told that, even if you have it set to outside air, the damper closes as soon as you turn the car off. In Tucson w/ 100+ temps and AC always on, that traps a lot of moisture and it heats up fast. So the smell is there even if you turn the car off for only a few min.

[markoneus]

I've just been searching on this topic, too (for my E36 M3) and people say it's either the microfilter that's become covered in mildew and needs to be changed, or the evaporator drain is clogged and has foul water stuck in it...

http://forums.bimmerforums.com/forum...ighlight=smell

[Qsilver7]

... In Tucson w/ 100+ temps and AC always on, that traps a lot of moisture and it heats up fast. So the smell is there even if you turn the car off for only a few min.

Hmmm, in your special climatic situation...I can understand not wanting to turn the AC off a few minutes before your destination. Have you tried using the VENT ON feature? When you get to your destination, turn the ignition to POSITION 1 and press the VENT ON button, then remove the key and lock up the car. The HVAC system will run "non cooled" air into the cabin for up to 30 minutes, or when you return and turn the ignition on. This may help prevent the build up of micro-organisms since they need a hot moist environment.

The OBC offers 2 kind of timed venting features when you press the CLOCK FACE button on the MID (if you have NAV you'll have to refer to your NAV manual for initiation instructions):

• VENT ON (only appears when ignition is in POSITION 1) - the HVAC system will run for 30 minutes without the key in the ignition...or will turn off as soon as the ignition is switched back on.
• 1TIMER2 - the HVAC system can be "pre-programmed" to vent the car "up to" 30 minutes. A car start is highly recommended between timed events since this feature consumes a lot of battery power especially if the maximum time of 30 minutes is used.

[Bruce SEA 993]

I am going to try the Febreze route...in fact I pulled it out this morning and is sitting on the desk right next to me.

Funny, I have had 2 cars with this problem: the '83 533i and now the 2002 540. Seem BMW never bothered to figure it out or fix it. Benzs, Volvos, Fords, Audis (4 of them) never had a problem.

I have tried to shut it off a mile down the road but geez, this has been going on for a long time. Maybe the Germans like stinky socks!

Cheers

[Jerrysull2]

+1 for the great info!

I got the same problem, but I'll just deal with it for now.

[McCandless]

As "chiefwej" mentioned my "permanent" fix was to wire the air duct doors into the "fresh air" position. That was over a year ago. The "dirty socks/dead fish" smell gradually faded away and has never returned.
I did it by removing the under hood L&R air ducts that run between the microfilter housings and the firewall, removing the L&R underdash covers, and while laying on my back under the both sides of the dash, exercised the HVAC system until I figured out which motors and cables did what. It's the two Bowden cables marked with red and blue. Unclipped the respective motors (one on each side) from their mounts (leaving them electrically connected to prevent bus errors), tiewrapped them out of the way, and wired the doors into the fresh air position. No muss, no fuss, nothing cut, removed, or destroyed. Could be put back to "stock" in just a few minutes.

[540IASport]

Odd as this may be, what got rid of the mildew smell for me was setting the dial on the vent to the "white" selection. I had noticed that the dial was set on one red dot and I was getting a good amount of bad odor. After switching to the white dot, the smell disappeared. I reset it to one red dot and the smell came back. I did not add any disinfectant or do anything else.

Can't hurt to see what your dot selections are at.

[redsrover]

Yeah, I noticed a drip spot on the concrete under the engine, near the tranny side, after my wife drove the car off to get the kids today. It was warm yesterday when i parked it with the AC on I guess.

So does the condensation build up, get trapped, then release in a puddle (not puddle but enough moisture to form a 6" diameter wet spot of midewy and green tinted water) down on the ground when cranked up?

Just curious.