It depends on the engine in question, but if a distribution chain sounds, or the tensioning skate has been broken or the chain has stretched and that is why it is released. The chains are stretched by a use to high regimes of turns or by a lot of mileage.
Depending on what you find like this you will have to do. If, when the lid is opened, the skate presses the chains and still sounds so it is time to change the whole set (tensioning skate and distribution chains)
if on the contrary the skate is lazy and the car does not have many kilometers or is very \ "burned \" because it will be enough to change the tensioning skate.
All the best.