 Poorly performing weatherstripping should be reported to the car dealership if the vehicle is under warranty, as fixes may be known.Automotive weatherstripping is commonly made of EPDM rubber, a thermoplastic elastomer (TPE) mix of plastic and rubber, and a thermoplastic olefin (TPO) polymer/filler blend.Sunroof weatherstripping can also be made from silicone due to the extreme heat encountered by automobile roofs.