Ive had my mk1 172 for 3wks and I have to drive with the air con on all the time, as soon as i turn it off the side and back windows steam up instantly, even if the hot air is blowing full. It doesnt even have to be rainin outside for it to happen
Ive also noticed a draft coming in from outside on the drivers side below the steering wheel near the drivers door, if I turn off the air circulation thing then the draft goes away, could this be linked to my steamy windows problem?