ozone effectiveness at removing A/C odor?

W

wolfe

New member
I have a recurring issue with the A/C in my '04 bmw 330.



In fan only mode, it's fine. In A/C mode (recirc or external air) it's fine.



If the A/C has been on, and then you switch to fan only mode, it smells horrible for a couple of minutes. The smell is a damp musty one, I frequently see other bmw owners with the same issue describe it as a 'damp gym sock'.



I've tried several off the shelf evaporator core cleaners, and have sprayed the evap core down thoroughly with lysol no-rinse sanitizer. I've taken the blower motor out and thoroughly cleaned the fan blades, and cleaned the housing thoroughly also. The cabin microfilter has been replaced with an activated charcoal version. The evaporator drain is not blocked as far as I can tell.



No matter what I've tried, the odor still returns. Nothing has knocked it out completely for more than a couple of days.



Would an ozone treatment be worth a try, or is it also likely to be a temporary fix only?
 
Thanks for the info.



A couple more questions then:



1. Does it remove smells permanently?



2. I briefly spoke with someone at carmax's reconditioning center, who said they run their ozone treatment for 8 hours. Does this sound about right? I'm hoping the car wouldn't be idling with the A/C on for this long.
 
wolfe said:
Thanks for the info.



A couple more questions then:



1. Does it remove smells permanently?



2. I briefly spoke with someone at carmax's reconditioning center, who said they run their ozone treatment for 8 hours. Does this sound about right? I'm hoping the car wouldn't be idling with the A/C on for this long.
Click to expand...



Oh the topic of ozone. I would have never tought that I would be using my OZone machine as much as I do. The main thing with using ozone to kill odors is producing a large amount of ozone in a particular area. Depending on the machine filling a car with ozone can take minutes (more expesive machines) or hours (lesser ozone generators) to not at all (small air cleaners). In fact the small air cleaners (ion generators) I think do more harm than good, after having a thoroughly understanding the harmful effects of ozone.



Ozone shock treatment, however can be a benfical step towards permently eliminating "some" odors (ie mold, mildew and tobacco smoke). For treating the AC you would place your ozone generator (depending upon the machine) in the car or on top of the car, with it placed on its highest setting, blast your AC on the coldest setting and with the fresh air setting. Close the door and let the car idle for 15-20 (again, depending on the machine) mins. After that the ozone should have treated the AC. If you do a search you can see past threads about ozone.



Also for your air conditioner an ozone shock treatment can help, however here at my shop we find that some ac systems require an evaporator cleaning (escpecailly on older cars). Sometimes just spraying Lysol in the air intake cowl can also take care of the mold and mildew odor from the AC. As with any odor, you can only eliminate it when you know where the source is.
 
I've had this excat problem with my solara. The smell was horrible. What really worked and totally got rid of the smell is ozium spray. I used it once a day for three days and no more smell. Just spray in air vents with fan on. You can get it at auotzone.
 
I have this exact same problem! Every time I bring my car to the dealer for anything during the warranty period, they tried some sort of treatment for the smell, said it was very caustic and should have removed the odor. They mentioned it was some machine, not sure what exactly. Another dealer used some spray (frigi fresh I think), but that didn't work either. In any case, nothing worked, it still happens every time I run the AC. It's probably been treated 4-5 times by the dealer. And I've tried lysol myself into the AC vents from the outside, only lasts a short time and the smell comes back.



One thing I heard of but didn't try is some frigi-clean treatment which injects foam into the whole system which I guess would do better at getting directly at the mold or whatever is causing the problem. I can see how it could do a lot better than just spraying and hoping it covers things. And could probably clean off stuff that just ozone in the air wouldn't be able to touch.
 
on a side note, if it is happing really fast and often be sure to check the drain tube. After running the AC you should get a puddle of water under the car just in front of the passenger area. If you aren't then the drain tube is plugged so water is collecting in the system which will cause it to go bad fast.
 
Possible cause of the problem is not switching off AC for a couple minutes before you shut the car off.



I have read that a 3-5% bleach solution sprayed into the vents, and a wipe down if you have dismantled the core, will kill the mold. Not sure if it would beach the carpet at that strength if it dripped. Plastic just in cause might help.
 
bcwang said:
One thing I heard of but didn't try is some frigi-clean treatment which injects foam into the whole system which I guess would do better at getting directly at the mold or whatever is causing the problem. I can see how it could do a lot better than just spraying and hoping it covers things. And could probably clean off stuff that just ozone in the air wouldn't be able to touch.
Click to expand...

:bigups

We do this treatment at my shop and the success rate is pretty good. The foam is injected into the ac evaporator, where it kills mold and mildew.
 
The odor is caused by fungi and bacteria on the evap. coil. When your a/c is running the amount of condensation normally produced will wet and wash this stuff and its odor down the drain but when the compressor is not running the coil gets warmer and dryer and the odor blows into the car.

An over or under charged system will make this worse due to the compressor short cycling.
 
Thank you all for the advice.



My drain tube isn't blocked, I definitely get the puddle under the car. I have tried ozium, lysol, and two wurth products (fogger and ac cleaner) but all only provide temporary solutions. The most extreme thing I have tried is throughly spraying down the evaporator core with a lysol no rinse santizier solution (I think this used to be a BMW procedure until they switched to the wynn's aircomatic machine).



In all cases the damp smell comes back within a few days, but it seems to only be noticable when the core is not cold. After cleaning it, if I switch the A/C off I will get a blast of the foul odor, but if I switch the A/C back on, I can again smell the cleaning solution.



I have a couple of cans of the foam to try - it has a long tube with a weight on it, and supposedly you feed it though the center air vent down to the coil. I may give this a shot then find someone who can do the ozone treatment.



I will also get the refrigerant checked.



Thanks again for all the help!
 
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