OEM Part Number: ?. 38123; 419203; 45877; 49223; 5877; 89236; BT23; BT37; SK89236; F2TZ 6B209 D; F5TZ 6B209 D. Dorman 419-203: Automatic Belt Tensioner (Tensioner only). Dorman 419-203 Accessory Drive Belt Tensioner Assembly Compatible with Select Ford Models.