This car sits under a cover for an unfortunate amount of time. It's a 2007 and only has 39,000 miles, if that's any indication. It probably only receives love during the summer and sporadically throughout the year - it goes as long as 4 months without being touched.

Last time I uncovered the car, there was this awful mold/mildew smell coming out of it. Now, I live in a forest on the Eastern Shore of MD, so that's not too unreasonable. My father & I have tried a few things so far:

  • There was a lot of pine needles / dirt / debris in the little nooks under both the trunk lid and the hood (think door jamb but for trunk, can't think of the name). We vacuumed this all out and this had the largest (positive) impact on the smell.
  • Cabin air filter is whiter than my socks
  • Spare tire compartment is as clean as the day we bought the car
  • We've cleaned all over the (visible) interior of the car, but we haven't taken anything apart.

My dad also noted that when he drove this car regularly, he always left the A/C on "Max A/C" which leaves the recirculate feature on. As I understand it, this could have let mold build-up in the A/C system. However, I usually drive without A/C, and if I haven't used the A/C all day (windows down) and come back the next morning, the car still smells.

The smell is limited to the interior and the trunk. It's definitely not too severe (it was plenty worse before we cleaned out all of the pine needles). My dad think's it's concentrated in the trunk. I don't agree (but thought to offer his opinion in case it leads to something else).

Any advice on what to look at next would be greatly appreciated.

  • I have an old Honda Accord that sat in the woods for a while before I bought it. When I first got it the interior smelled like mildew pretty bad. The insulation pads underneath the back seat had started to mold. Jul 27, 2015 at 20:26

3 Answers 3


Mold needs moisture and darkness to grow

  1. Pull the car out into the driveway and roll down the windows
  2. Sunlight will kill whatever is exposed
  3. Get this stuff https://moldzyme.com/
  4. It works best when atomized - a sprayer can get close
  5. Remove the cabin air filter https://www.youtube.com/watch?v=wrTcTbUux2o
  6. Run the HEATER at full blast and spray the car with moldzyme - let the HVAC suck up the moldzyme mist
  7. Wipe down all surfaces with moldzyme
  8. Take her down the highway at 100 MPH and blow that sucker out!

You have started correctly by cleaning the interior of the car. Keep it clean and eliminate physically any mold present, this always helps prevent the spreading.

Mold also requires some degree of moisture; your problem would probably not happen in places with 50% or less of relative humidity. There is not much you can do about the weather, but you can use desiccants to lower the humidity inside the car while it is stored. Silica gel is often used to package electronic parts (hard drives), and can be placed inside the car to lower water content. There are several brands used as cat litter, so check with your local pet store as this may be an effective way of obtaining a couple of pounds of the stuff for not too much money. Make sure the vehicle is well-closed during storage.

Finally, just a thought: motor vehicles do not really like just standing around. The wheels will suffer from immobility for one, and there are quite a few gaskets in the engine room that need movement to remain properly oiled all around their circumference. So I would really encourage you to find someone willing to take the car for a 30-minute run from time to time, even if it does clock up some miles over the years.


Here is a video that shows the process.



I had a Mercedes that had a problem of mold growing on the leather. We had to get a anti mildew leather cleaner and take it to the leather.

  • 5
    If you could spell out the basic steps for the process, you'll get a lot better reception of your answer. The problem with links only is the links can become stale (like nobody has ever deleted a YouTube video, eh?). Take a couple minutes and flesh out your answer and I'll upvote it for you. Jul 27, 2015 at 22:34
  • I second Paulster2's comment.
    – NULL
    Apr 8, 2016 at 17:13

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