As it's name implies, it covers your timing chain keeping the Engine Oil in & dirt & debris out. On 79-95 5.0L Mustang, it also acts as the mounting location for the Mustang Water Pump & houses coolant passeges in to the Mustang Engine Block. On 96-04 4.6L Mustang, it contains various mounting points for the Accessory Drive like the Belt Tensioner & Idler Pullies.
