Air Conditioning STINKS!!!!!

Ok, this one has me completely stumped. Ever since I've had my car (3-4 years) I've noticed that if the A/C is on when the car is turned on, there is a horrible stale sour smell that comes through the vents. After a minute or two it goes away. I noticed that if I started the car, let it run for a minute, and THEN turn on the A/C, I didn't get any unpleasant smells.
Well for the past few days, whether I wait a minute before turning it on or not, it has that same horrible smell! And now it's seems about twice as potent! What in the world is causing that?? In every case the smell completely goes away after I drive for a minute or two. :confused:

Don't think the Grand Prix has a cabin filter but it may be something you want to look into. My girl's Taurus smelled horrible with the air on. Replaced the cabin filter and still stunk. So I heard someone suggest to buy a bottle of lysol, turn the air on, and spray the whole bottle into the outside intake. The lysol will run through the ducts and improve the smell. I think water gets in there and they get moldy. It stinks!

That's a good suggestion. Do you have any idea why the smell would go away after a minute?

Tell you the truth Matt, I think Hungry Cat is correct on the mold issue. Not sure if you had to repair your intake cowl seal (due to water on the passenger floorboard), but mine does the same sort of smell sometimes and I attributed it to the water leaking in so ofter. The cowl seal was leaking when I bought the car.

You could install a cabin air filter, but you have to order one from a like year Buick regal because GP's never came with one. I think mine was 14 bucks last year.

Also, I think GM makes this can of cleaner with a long hose on the end. Basically what you do is insert it into your vent, and push it in all the way, spray it and move it around to try and get it all over your evaporator. Its supposed to clean the mold off of the evaporator. Maybe its worth a shot.

Hmm. That just confuses me because of how dry and hot it is here. I just don't see how mold could survive! I'll definitely give that a try though. I know I have some lysol spray lying around at home.

If the horrible smell is sour/vinegary, then you have a refrigerant leak. If it's a musty smell, then it's mildew buildup on the evap core as suggested above.

Mold can survive on the evaporator because when you run the AC when its hot and humid, due to condensation, water forms on the avaporator grid. Then you turn it off, mold forms on the cool wet evaporator.

You wouldnt believe how had I've seen some evaporators up at school. They were so plugged with mold that it was amazing that any air could flow through them.

I haven't the slightest bit of knowledge when it comes to A/C & heating systems. :screwy: Where are these things even located???

You dont want to know! LOL

The evaporator is a bit harder to remove than the heater core. And I think the the grand prix's, the dash has to be removed.

Ah. Well screw that. So just spray some lysol down the vent and I'm good? Is there anything that I can easily get to that I should look at as well?

Not sure lysol will do much, but there is GM "evaporator cleaner spray" that might work. Check with the dealership.

Then put in a cabin air filter, you'll be good!

K, sweet.

Here is the cabin filter replacement link... http://www.mccgp.com/upgrades/cabinairfilter/air_filter_new.php Save you from searching later.

:rolleyes:

Which climate control system do you have? The manual single zone, the manual dual zone or automatic/digital (ACC)?

Regardless you should have RECIRC (MAX) and UPPER (NORMAL) modes. The mildew smell will be prevalent if you run too much RECIRC/MAX mode. Reason is the moist air conditioned air is drawn in via the cabin and not the HVAC intake cowling and cabin air filter, if installed. Using the UPPER/NORMAL A/C modes dries out the air and reduces the mildew effect.

Although it may help with mold or fungus spores that cause the mildew smell a cabin air filter's primary purpose is pollen control. And as I pointed out above the cabin air filter is not used in the RECIRC/MAX modes. :grinno:

You can get special aerosol spray at the auto parts stores that will help eliminate or kill mildew. In the UPPER mode with A/C compressor button off and blower in max just spray the stuff directly into the HVAC intake where the cabin air filter is located. Of course remove the cabin air filter first, if installed. Also, those aerosols will leave a nice smell since they have air freshener in them.

I have the dual automatic option. You were absolutely right! I stopped running the "RECIRC" button for a few days and the smell is gone! I'm sure like you said, if I did it a lot again, it'd probably come back. I'm going to go get some spray stuff too! Thank you for your help!!!

Another thing to check is the "drip outlet" for the evaporator.

MY brother's GTP (soon to be mine) had the outlet plug up or get sticky...anyway, I was underneath probing the firewall to find it...when I did it knocked something loose and I was getting hosed with a steady stream of water.

In his case it was so bad the driver's and passenger floors were getting wet. But definitely something to check on. It is frustrating to find but costs zero to fix. It is somewhat hidden so it doesn't get "reverse flow" due to the vehicle speed and ingest rain.

Interesting. Can you give me an idea of where it is located?

Matt, just turn the AC on for a small trip. When you stop and turn the car off, look to see where the condensation is dripping out.

The drain hose is located at the passenger side firewall down low. Never hurts to make sure it is not clogged and as Tim suggested you should see condensation leaking from it from the A/C evaporator core when running the A/C. I get it all the time especially when humidity is high.

However, that drain hose can be working properly and you will still get the musty/mildew smell. As I mentioned earlier do not run the system in the MAX/RECIRC mode too much or at least run NORMAL/UPPER for several minutes before shutting down. And run the mildew killer aerosol spray through at least once a year timed in conjunction with a cabin air filter replacement or cleaning, if installed.

Sounds good. Next time I'm under there, I'll take a peek.