I had a 1996 Laredo and in 1998, the evaporator was replaced on warrantee because of a foul odor due to mold accumulating on the evaporator coils (I was told). It was always kept in the garage and not outdoors.
Around 2002, the odor returned, and I kept it at bay by frequently spraying the inlet with a bacteriostat with only some success. Needed to do it twice weekly.
I have a 2001 Laredo now and it is OK so far with no odor problem. This one is also garaged full time.
Can anyone give me any information as to how this happens and if I can do anything to prevent it from happening to the 2001?
There is a product that is available from most auto suppliers that is made to clean the coil and sump are under the coil, just follow the directions on the can. From what I have read this is a common problem virtually in all auto makers HVAC systems.
This is a problem with most all cars that were originally designed to use R-12 refrigerant (freon) and then converted to non-freon R-134a in production.
To help these systems cool better manufacturers used more cooling fins on the evaporators than they did with the older R-12 systems. This provides more surface area for cooling, but the restricted evaporator cases often provided less air circulation and thus mold forms more easily on the damp evaporator fins & coils. Later systems were deigned for better air circulation and have less of this problem.
All you can really do is to treat the system periodically with AirSept or any other bactericide as you have been doing. In some cases the evaporator can becoe completely clogged with dead and growing bacteria. Aside from it stinking to high heaven, some folks can get a severe respiratory infection from it, even Legionairres disease in extreme cases. If the system is not circulating properly ytou need to depressurise the system and pull the evaproator for a thorough cleaning, or even replacement.
Aa a buddy once said: "We've saved the ozone layer with R-134a so peeople won't be killed by ultraviloet rays before we can kill them off with A/C mung."
Every once in a while I turn the A/C on and crank the fan up on high and spray Lysol into the outside intake for about 6 seconds. I then turn everything off and leave the car sit with the windows open for about 20 minutes to air out.
Stay out of the car during this time because breathing that much Lysol isn't very good for you.
Next I run everything on high again for another 20 minutes or so to help flush the rest of the Lysol out (again with the windows open) and again I usually sit in a lawn chair and have an iced tea so I'm not breathing that stuff.
Generally speaking I do this about once a month during the spring/summer and so far (knock on wood) I've never had the HVAC grunge. Of course ymmv.
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