AC Moldy Smell

thayes1413thayes1413 Member Posts: 1
edited March 2018 in Cadillac
I have a 2017 XT5 that I love everything about, except for the awful smell that comes out of the AC during warmer months. I've taken it in and had it cleaned a couple of times. They tell me to run the AC in the fresh air mode (non recycle) but the Automatic function defaults to this. This is the first time I've had this issue on a car. I'm wondering if anyone else has had this issue or it it's just my car.


  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    You might GIVE THIS METHOD a try. This is a short video

    No, it's not just your car! It's a common problem.
  • gmcustsvcgmcustsvc Member Posts: 4,252
    edited March 2018
    Hello, @thayes1413 . We regret to hear that you are experiencing this concern with your XT5. We understand that you are seeking advice from other forum members; however, please know that our team would be happy to look further into this AC concern with your dealership. If this is something you are interested in, please e-mail us at socialmed[email protected] with “ATTN: Cadillac/thayes1413” in the subject line.

    Please be sure to include your contact information, VIN, current mileage, and the name of your servicing dealership so that we may best assist.

    To review GM's privacy policy, please visit the link below:

    Jenifer J.
    Cadillac Customer Care
  • imidazol97imidazol97 Member Posts: 26,995
    edited March 2018
    There is a GM TSB for this problem. Your car should be within warranty. The TSB applies a coating to the metal of the AC unit and the area to prevent microbial growth.

    Your car should have the ability to turn on After Blow, which keeps the fan running moving air across the AC fins to dry them after the car is turned off for a few minutes. The TSB may include a module change to enable that if yours does not have it. I do that in my cars by turning off the AC a few blocks before I park them. I turn the blower on high to try to remove moisture. I also leave a window down an inch on a side to draw air through the car and the HVAC when there's a breeze and the car is sitting outside.

    #99-01-39-004I is the TSB number
    The document is attached to this post as xt52017pdf.pdf
    Check with your dealer.

    This type of service has been used on several GM cars where the humidity stays in the HVAC box.

    You mention the AC reverts to the Recycle mode, despite your turning the setting to fresh air (flow through) intake. The HVAC unit goes into recycle to speed up cooling. Set the request temperature to 75 or so and see if the unit will stay in flow through mode after being driven for 10-15 minutes.

    2014 Malibu 2LT, 2015 Cruze 2LT,

  • imidazol97imidazol97 Member Posts: 26,995
    edited March 2018
    The video shows using an antimicrobial spray putting it into the air intake. Remember to take out the air filter for the cabin air. Otherwise, that cabin air filter will catch and hold a lot of the mist instead of the mist coating the inside of the HVAC box.

    Also, do it after the car has sat for a long time and the AC coil is dry. DO NOT RUN THE AC, in my opinion, because that will cause the evaporator coil to condense moisture from the air onto it which will dilute and remove the spray you're hoping to have stick to it.

    I'd let the car sit for a few hours after treating it.

    One spray suggested was Lysol. I have used that a couple of times long ago. It's hard to stomach getting into a car after it sat overnight with Lysol coating the HVAC box. Driving with windows wide open and blower on HI did not help much... LOL This lasted at least 10 days of commuting to work and back.

    I would try to get the other spray that's targeted and scented for this purpose.

    The GM dealer may actually insert a small tube directly into the area of the AC coil to coat it. Bonneville owners used to do it themselves by drilling small hole in just the right spot, filling the HVAC box with the GM-approved foam, and letting it sit, shrink, and dry to prevent the mold growth.

    2014 Malibu 2LT, 2015 Cruze 2LT,

  • anytimehvacanytimehvac Member Posts: 1
    I think the basic reason of smell coming out of AC due to clogged condensate drain line, because trapped water can quickly lead to bacteria growth and start producing bad smell.
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