2008 HHR SS 18,000 miles

It's a warm day for St. Louis in November (78) so I turned on the AC for the first time in a few weeks.

It smelled like mold or mildew for about 5-7 minutes. It was a pretty strong odor.

The smell went away after the first 5-7 minutes.

Ideas? Suggestions?

The car is still under warranty but I am looking for some knowledge before I take it in.

THANKS for the help!

 

Replace the cabin air filter.

 

Check the cabin air filter, behind the glovebox, it's probably pretty dirty.

 

Thanks guys!

I pulled the filter. I was a little dirty. I put the shop vac to it and hit it with a shot of Sport Febreze.

I'll replace it tomorrow if it still smells bad.

 

I have noticed that "smell" since my 2010 was just a few months old.Usually goes away in a couple minutes like the OP stated. I have checked for any water leaks(all clear) and pulled the cabin filter(all clear) and sprayed it with Febreeze(worked for a few days).
Conclusion for me is,high humidity. I live in an area known for it's very high humidity levels,re:the Gulf Coast.That along with the filter trapping and holding humid air while the car is sitting unused for long periods,1-3 days.
We recently had a rare occurance of extended low humidity weather. During that time I did not get that "smell" at all. I think it is just a combination of the filter and humidity. At least in my case it is.
Thinking about pulling the filter out and driving for 1-2 weeks and see if the "smell" goes away. If so then maybe I'm onto something.

 

It's definitely the humidity. This summer was bad here because of it. The smell from the vents at AC start up was like a locker room full of sweaty cheerleaders (don't ask how I know). Not only in my 09 HHR but in my wife's 05 Cobalt. I read something a while back about dealers (not necessarily GM, I think I read it about Ford) having to clean and then coat the AC unit in the dash to kill the bacteria that grows readily due to the moisture and nowhere for it to dissipate. I semi solved the issue by turning off the AC a mile or so from when I get home and just leave the blower on high on heat with outside air to dissipate the internal moisture. Do not have recirculate on, the Ac stays on even with the light off. It also helps to have an activated charcoal cabin filter. I just bought FRAM Fresh Breeze Filters (cobalt & hhr the same) part # CF10361 which also contains baking soda, There was a closeout sale in Wally World near me because the were redoing the store. I picked them up to swap out next summer.

 

Yeah, that did NOT work. I'll be buying a new filter.

Not good...

 

I do same thing, shut off A/C a mile or so from home & seems to dry out the ductwork etc.. At any rate no musty stink..(edit): I also always have control set for outside air. ..

And those filters are said to be really good..

 

Seems I have read there is something you can spray into the intake while its running to disinfect the ducts etc. Can't recall exactly what, but I would think something like Lysol would certainly help.

 

Like Sleeper says, Turn the AC off for just a few minutes before you reach your destination, but leave the fan on. That seems to blow out any condensation from the system. When that moisture is allowed to sit in there, especially overnight, you get a musty smell when you first turn the AC on again. That's worked for me anyway, even on previous cars I've had.