So I've got this weird water leak that I haven't been able to diagnose yet. I've cleaned both the rubber grommets and replaced the weatherstrip above the door and it's still flooding. Any ideas? Pics included.

 

Make sure that plastic trim is snapped in correctly. Check the quarter window seal and door by pouring a glass if water down while someone inside watches for the leak.

 

Just poured a gallon of water on the door/window after drying everything up and there was zero water on the floor. Any other ideas?

 

Did you dry up all of that water that was sitting on the floor? Is water still collecting there?

It's not coming from the floor. You have a seal leak someplace in one of the glasses or trim. Ie. quarter, back, or drivers. I still think its due to one of the trim pieces around the door.

Also, notice that the newer mustangs window glass slides up automatically about a half inch after you shut the door? Make sure your car window is working correctly. You can even slide a piece of paper in between the glass and seal to test. With a good seal, you will crease the paper and won't be able to slide the paper out. This will help find a seep area more easily. Hope this make sense.

 

Edit: Or since you dried everything up and no water got in. The glass just may not have slid up all the way. It happens. If it does it again after washing or a rain then we have a problem.

 

take it to a pressure wash and have someone inside the car then hoser down.

 

So I washed the car and there was no water anywhere. I really hope it was just the window not rolling up all the way. I'll have to take it to the car wash next weekend and see what is going on.