Here are my suggestions on how you can prevent and even completed iradicate interior condensation in your car.
Look for signs of damp – it sounds obvious to some, but condensation is caused when warm air in the car comes into contact with the cold glass of your windshield, thus turning from a gas into a liquid. Anything in the car that is damp will give off moisture which will turn into steam usually invisable unless it’s really cold outside) which in turn will turn into water as it rises and collides with the windsreen. Check for leaks (especially in the boot/trunk). Lift up the rear carpet and make sure the rear wheel well isn’t damp or full of water. If it is, don’t panic.
Leave a couple of windows slightly open on warm/sunny days. – If you’ve read the above you’ll already know why condensation occurs. Leaving a window slight ajar during warm winter days will allow the sun to warm the vehicle’s interior and leaving the windows open will allow the air to circulate the moisture, thus “airing” the vehicle
Close you window on wet days. – Obvious, huh? But you would be forgiven for forgetting to close a window properly or even the sunroof. I’ve done it. Haven’t we all? Make sure your doors and windows are properly closed especially during rain or heavy dew.
Use your air-conditioning. – But it’s winter! Who needs air-con in the winter? Well actually, you do. Some people may be familier with a little puddle of clear, odourless water forming under a car in the summer; usually caused by the air-conditioning system dumping water which is removed from the atmoshere during cooling. It works the same in winter. Your air-con will remove damp from the air – even in cold months – so once your car is up to running temperature try using it. That aside, you should use your air-con at least once a fortnight during the winter to keep the system “ticking over” and stop any pipes trying out and consiquently leaking gas. It also stops it from smelling. Smelly air-conditioning?
Turn off your re-circulation (recirc) valve. – All cars have them, especially cars with air-conditioning. A lot of people haven’t got a clue what it is. It’s usually shown as a picture of a person being smacked in the face by a huge arrow (or sometimes a “C” shape with an arrow on this end).
Try an anti-fogging product. – I recommend Rain X Anti Fog Repellent which I use in both of my cars.It can put a slightly visable film on the window at timesRemove wet clothing from the vehicle at all times – sounds obvious, but it’sDry wet seats – use your heaters and direct heat onto the seats to dry them. Open the windows if it gets too hot.
Remove rubbish on regular occasions – leaking bottles, moisture left in cans and rotting apple cores all create moisture and non of this is going to help your cause.
Air the vehicle as often as possible. – Put the heaters on full and open the windows when driving if you can. Direct the air vents on the carpets and seats when possible.
Use your garage. – The ambiant temperature in the garage with be higher than outside in the winter and prevent damp. You can also leave the windows open to help air the car if the garage is secure.
Avoid car covers. – Some car covers claim to be breathable but I’m not convinced. I also had one damage the paintwork on a newly painted MGB GT some years ago (due to a chemical reaction – nice pic of the car above) so I don’t trust them.Park the car in the sunshine with the windows slight open. Only if it’s safe to do so, of course!