Why is my BMW overheating after I we put in a serpentine belt

Hello, did you breach the cooling system ever? Would purging air out of the cooling system be required? It's not about the belt, it's about the transmission cooler. No overheating before this work done? Must be related. Impossible to guess from a computer -hands on testing is needed. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops