Did you have a recent tempereature change in your region? That can cause issues with drying.
I went through some drying aid issues a while back. I think I even posted on the forum for some help.
I wasn't satisfied with how things were going with what I had. I switched to a product that uses no mineral seal oil. It is a low pH product that does a superb job for me, and since there is no oil, I don't have any streaks or smears from build up on the windows, as some can cause. Keeps the wash cleaner, and has a great scent that stays on the car. By far the best product I have used, and I have had some "bigger" and more expensive name brands over the years.
It is called Shining Armor by Jobe. Jobe also has several other similar drying aids - some might be better suited for different operators and conditions. They are all available at
Kleen Rite.
Good luck.
Mike