Preventing Mold in Infrequently Used Car?

[TrMama]

I've started biking to work 4-5 days/week. Plus I usually only drive once on the weekend. The car is parked outside since the garage is full of the family's bikes. We live in the PNW and rainy season winter has arrived. I drove today and noticed there was quite a bit of condensation on the inside of the back window. It looked like it had been there a while and I'm concerned the inside is going to get moldy.

I don't want to leave a window cracked open for two reasons. One, rain will get in.  Two, we live in a high crime area and I don't want the car to get stolen or vandalized.

Ideas?

[JessieImproved]

Get a big tub of Damp-Rid (or other moisture absorbing pellets).  They can usually be baked in the oven and reused.

[Mr.Macinstache]

I think charcoal does a better job and is cheaper...

Odd that it is getting moisture inside..one of the seals must be broke.

[Greg]

Step one is try to find the leak.  Could be a door seal, a window gasket, or a leaking heater, sunroof or cowl drain.  If you locate the leak, you may be able to fix it.  If you can't fix the leak, try to create an escape for the water in the form of drain hole in the floor.

Sometimes the trunk can collect water, and it can cause this condensation in the passenger area.  The spare tire well is a common collector of water, but often there's a drain in there, sometimes plugged with a rubber plug.  Remove it.

To prevent mold, clean the upholstery.  Mold needs moisture and food (dirt) to grow.  Another option is a corded light (incandescent bulb) left on inside the car.  The heat will help dry the moisture.  Dri-Z-Air is one brand of moisture collector you can get, but you have to empty it and carefully (becomes acid when it collects the water from the air).

Might be time to re-organize the garage so that the bikes and car can live in the same place.  Another idea is a waterproof car cover, they're less than $100 usually.

[unpolloloco]

I'd bet that the cause is just normal humidity in the air.  Last time the car was driven, it was probably warmer and humid.  When the car cooled down overnight, the humidity condensated on the coolest parts - including the window.  A car cover's unlikely to solve the issue (other than making it a darker place inside the car, encouraging even more mold growth).

It's probably not a big issue, so long as the car's driven every week or so with the AC and/or heater on (or windows down if it's a dry day) to reduce the interior humidity.

[No Name Guy]

Its Seattle. 

Condensation buildup in an unused vehicle is a fact of life, even without leaks.  It rains....a lot.  This time of year, it's cold and high humidity, without much sun. 

Even with today's weather (mid / upper 30's overnight with copious fog and dew, bright and sunny mid 60's day) you'll likely get buildup inside - park the car in the evening when it's still mid 50's, well, it's 60% humidity air you're trapping in there, not counting if it had been raining or wet at all and your wet feet / coat brought in a bunch of moisture as well.  Cool it off to the mid to upper 30's over night and it's going to condense over the inside of the windows.  With it being all sealed up, there's no way for the moisture to exit.

Run both the heat AND A/C at the same time for a while before parking - the A/C coils will condense out the water (which will drain via the normal AC drain), drying out the air, then the "hot" setting will warm the air.  The GF's Toyota owners manual recommends this procedure for dealing with a lot of window fogging.  Check your owners manual for their recommended procedures.