Mine are full of radiator, their staying on.

 

When I'm home in the Summer I take them off. Gives me a chance to shine up the chrome on the entire crash bar. But when I head off on a long trip (in a month I'll be headin up to Upstate NY) they are back on.

 

I leave them on year round. I opened the doors completely and then marked a line with a sharpie on the door. I then removed the doors and used a dremel tool and cut the part off that was blocking the opening. Now no need to remove the doors. I get full amount of air (HUGE DIFFERENCE) this way. Also note when closed you still get good protection in the winter and in hard rains.