Well actually its not so much that your not suppose to, its that it can cause problems. If you let the soapy water dry on the car while your washing it, it can create streaks or spots. More common is the problem of getting water spots when drying. Its not bad to wash your car in the sun, its just harder to do a good job. There are a few things you can do. First and most simple keep the car wet while your washing it and dry quickly. Second: buy a in-line water filter, this will reduce water spotting. Third: wash the car in the wee hours of the morning or at dusk. Fourth: Buy a pop up canopy.
Last edited by Thejoyofdriving; 09-09-2007 at 01:32 AM.