Just took in my 04 Trailblazer for an issue with a sour smell coming from the AC.... They did a "treatment" on the evaporator coil. I asked what caused this and was told it jsut happens..... Something like this does not just happen.... Something must have caused this and if so they didnt fix the issue but prolonged it.

Anyone out there had an issue like this and actually got it fixed?

Daniel

has your auto been in a flood? If you don't know, maybe you should do a car fax search and find out where it came from. There are a lot of people selling off flood damaged cars from Katrina and other flooded areas. Your problem is "MOLD" You need to take it to a dealer and have them clean it for you because this is very unhealthy for you and can make you sick.

I don't know if I'd call the issue most people have with AC as a sour smell but mildew is common. If you run the AC right up the second you park it, it will develop a mildew smell. There are several products to help resolve the issue. In most cases you spray the products in at the cowl area so it is sucked into the system. That's probably what they did. The mildew develops because the moisture, that is the by-product of cooling the air, sets in the system. If you shut off the compressor but run the blower (vent setting) it will allow that moisture to evaporate. You only have to shut it off a little way from home.

Holy crap---didn't notice the age of the original post

Like tahoe07 posted this is common and it does happen with any make of vehicle.