This is just a quick personal question of mine that I thought I should see what you guys have to say. Basically, I'll just give you the scenario: My mom drives her 1997 740il home in the rain. It is about 65-70 degrees outside. My dad and I were working in the garage before she arrived. We had the doors open, but it was still about 80 in the garage. My mom pulled into the garage, with her car wet and warm. She notices the metal strip running under her windows on the exterior of the car is very cold and foggy. We close the door. This morning, pulling the car out of the garage the windshield is cracked BAD. We can't figure it out. Nothing hit the windshield. Was it the big temperature change? I'll take any input, gumshoes. Thanks for helping us figure this one out.

 

I lost a windshield once to water expansion due to heat. I had a tiny pock mark (spider) on the windshield. Water got into it one day, and after leaving the car in the sun for about an hour while I ran an errand, I too was greated by an end to end crack.