Every time I start the fan blower on my 99 VW gti after the car's been sitting overnight, I get this really nasty pungent disease kinda smell out of the vents. I open the windows and it blows away, and it's fine after the first 30 seconds or so.

So I decided to replace the cabin air filter. Yes, after 12 years. So I figure while I have it opened up, maybe I should spray some disinfectant or something else in there while I've got it all accessible. Good idea? Bad idea? Suggestions as to what disinfectant or anti bacterial spray I should or shouldn't use?

2 Answers 2


It sounds like it wouldn't hurt to spray some Lysol into the intake. I wouldn't spray it into the filter itself, though, since those are generally paper and would likely dissolve.

More importantly, I would strongly recommend running the heater for quite a while. If you get the system nice and hot, you will kill off quite a lot of the more horrible smelling mildew and the like.

We've talked about the smells you can get in your ducts before but Slink's answer nicely summarizes the high points of most suggestions.

  • my smell isn't tied to the A/C at all it happens just with the outside air, but I'm sure it's all related. The heater idea is a good one, hadn't thought of that. And being spring and summer for a while I haven't turned the heat on lately. Thanks for the tip.
    – stu
    Commented Oct 21, 2011 at 18:45
  • @stu, the issue with air conditioning is that running the AC can leave extra condensation in the vents. If the moisture is high in those vents, mildew will grow. At that point, the vented air will smell no matter what system you're using, recirc or not.
    – Bob Cross
    Commented Oct 21, 2011 at 19:01
  • Makes sense. I replaced the cabin filter, and it still emits the smell, so obviously the problem is after the filter (because there's nothing really before it except the vent to the outside. So you're probably right the smell is emanating from the vents themselves.
    – stu
    Commented Oct 24, 2011 at 0:44
  • 1
    did something get in there n die? mice have been known to next in airboxes in motorbikes
    – Mauro
    Commented Jan 19, 2012 at 8:27

Bob's answer is a good suggestion.

I had a similar issue with my 2005 Touareg. When it would get damp out I would get odd smells coming from the vents. I ended up replacing the filter and using this A/C Coil Cleaning solution on the vents, and it took away the smell. It might be worth a try if you can't get rid of the smell.

It's basically a foam. You shove the tube down the center vent and spray until the can is essentially empty. There are also some other air cleaner products on there called Odor bombs. Maybe one of those would work too for your situation as well.

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