Bear, Just a quick one for it if you can get the lend of a de-humidifier, If there is any moisture, it'l get rid of it, all you do is leave it in the car for a few hours best over night if you can, and you'l see how much water is soaked up, if the filter fill after only a couple of hours i'm afraid you'l probally have a leak as there'l be allot of moisture in the air in the car. , but if it takes the full night then you wont, it'l just be moisture gathering over the years with the car. make sure all doors are closed all windows are closed and leaving the heat running for a while cant hurt either will all help soak up the moisture. After you do this i doubt you'd have much troubles with it again for a good while, i used too valet cars and came across it quite a bit, and this always worked, Worked perfect on my old cars. Sorry not such a quick one after all.