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Discussion Starter · #1 ·
I discovered another problem with my A/C system. When I first start the car up, the fresh air coming into the car has a very bad smell. If I shut the fresh air off and go to recirculate, the smell goes away and all is fine. Today, I pulled the cabin air filter out (just changed it 2 monthes ago) and it was clean and had no smell. I pulled the driver's side plastic cover off as that's where the air comes in and it was clean with no smell. Rubber seal for hood is in great shape. Their are no exhaust or oil leaks. Not sure where smell is coming from? 2006 LTZ with a 3.9.
 

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I would pull the fan motor and check in there.

Edit: realized that was stupid after I posted it, that would be the same on fresh or recirculate. There must be something further into the ducts though, try to find a way to see further in, maybe by the blend door?
 

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OK, most likely you have mold growing on your AC core. What can be happening is water gets trapped because the drain tube gets clogged.

Clear the tube and the auto parts store has a deodorizer that works well.

Could also mean your core is leaking as well.
 

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Discussion Starter · #5 ·
It is not an anti-freeze smell, but could be a mold smell. The water drains on the ground when the car is parked but I've heard of mold growing regardless. They say you should shut the a/c off and just run the blower for a few minutes before getting out of the car to prevent mold. Right. There is no way anyone will ever do that. Wouldn't I be getting the mold smell with the fresh air off also? There is only one a/c box and blower.
 

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Your other post indicates your car is not cooling well. I think this is a connected issue. Meaning, if your evap core has a tiny hole. The oils in the freon collect stuff in the air. That hold moisture. That grows mold.

If you are draining when running the AC. Then I would say this is the issue. Sorry. But, it will be a expensive fix.

Yes, I do this for a living. If I came across a car with your issues. I would first do a evac on the system to see how much freon is in the system. This will tell me if you have a leak.

To be sure, if we wanted more evidence. We could dye the system and recharge. Come back in a week and I would use a black light to see the leak. Most likely have glowing water coming out of your drain.

So, that mean a new evap core. If you do it soon enough. You shouldn't have to replace anything else. Yes, running a AC system on a low system will destroy your compressor. If you want a heart attack. Check the prices on those.

If it was my issue and I didn't have access to my shop. I would buy a recharge kit with dye.
 

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OK, I just reread your other post. If your freon is not low. Yet, you have issue cooling. Odds are your moisture moisture collects the particals passing by as air blows over it) has clogged the evap core. Not letting air pass through which leads to your first problem. Second problem the evap core still gets cold and creates moisture. Which feeds the mold.

You need to get the airbox open and clean that thing out.
 

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Discussion Starter · #8 ·
I'm a retired Corporate aircraft mechanic (almost 46 years). Learjet 35's had a freon system to cool on the ground driven by a large electric motor, so I'm no dummy to this. It must be a mold problem and I will get a can of spray stuff to get rid of the smell. The car cools just fine if I shut off the fresh air switch and go to re-circulate. The air still comes from the same box with no smell. That's what has me mistified.
 

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I would like to look into this further for you. In order to do so, I will need some more specific information from you. If you could please send me your full name, address, phone number, the VIN for the vehicle, and current mileage, I will be able to take further steps. If you have further questions, please feel free to contact me directly. Thank you.

Tricia, GM Customer Service.
 

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GM is going to recommend you install an after blower. Mine was done under warranty. Mine smelled like raw (uncured) silicone after A/C was shut off for several minutes. There is a TSB for the afterblower. It works, somewhat. Essentially tries to dry the system out after you have shut off the car and are gone. Like just running the blower with no a/c for a few minutes as talked about above. It has reduced, but not entirely eliminated the smell for me. Also, I change the filter twice a year and spray Lysol in there (blower motor area) with the car running. Again, much better, but not 100%.
 

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GM is going to recommend you install an after blower. Mine was done under warranty. Mine smelled like raw (uncured) silicone after A/C was shut off for several minutes. There is a TSB for the afterblower. It works, somewhat. Essentially tries to dry the system out after you have shut off the car and are gone. Like just running the blower with no a/c for a few minutes as talked about above. It has reduced, but not entirely eliminated the smell for me. Also, I change the filter twice a year and spray Lysol in there (blower motor area) with the car running. Again, much better, but not 100%.
This shouldn't be an issue at all!!! GM should have to warranty it no matter what. Clearly there is an issue here. Like I said above my car only has 15k miles on it. It's practically brand new still. No car should ever be blowing out foul smells from the AC blower
 

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Do a google search. It is not limited to Chevy, GM, or American cars. Widespread issues across the board with funky A/C smells of this type.
 

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Discussion Starter · #18 ·
Yes, I agree. A lot of cars get this. They all recommend you shut the a/c off a few minutes before you shut the car off to avoid this. Who does that? No one I know. They need a better drain system. Maybe a drain that drains a little all the time and opens up wide when you shut the key off.
 

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Discussion Starter · #19 ·
Did you guys read the reply (or maybe it was a private message) from Tricia, the GM rep? She asked if I took it in to a Chevy dealer to have it looked at? If I did that, why would I be writing in here? Any wonder why, when I buy new cars, I buy Toyotas.
 

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^^ Isn't she great?
 
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