This component is one of the essential and consumable parts of a car engine. It consists of a bearing and a plastic roller on which the belt runs. It is usually replaced during timing belt service or replacement.
Failure of this part can cause serious engine damage, leading to timing belt breakage and ultimately bent valves. Early failure of the roller at low mileage may be caused by the ingress of dirt or water, or engine oil leakage into the timing belt cover. The first sign of roller failure is noise in cold weather.
It is recommended to purchase timing kit products as a complete set for optimal performance and durability.