The engine mount works by fixing the engine firmly to the car’s sub-frame, or engine cradle. It is one of several mounts that hold both the engine and the transmission together and in place. So that the metal surfaces of the engine do not jar against those of the car body, sending shock waves through the car, rubber is used to fill the engine mount or, in some models, liquid is injected. Vacuum-controlled or electromagnetic mounts are used by some car manufacturers to further control the absorption of vibrations. Problems are caused when the mount materials start to deteriorate. Cracks or breaks in the rubber will inevitably cause friction as metal clashes against metal, or if the liquid filler (where used) leaks out, you will probably notice a juddering sensation and increased engine noise. An engine mount cannot be maintained or repaired – it has to be replaced when it starts to fail.