The Mercedes-Benz radiator and coolant hoses make it possible for the coolant to go back and forth between the engine and the radiator, making it possible to control the temperature in the engine. This gives your Mercedes-Benz a huge advantage over older vehicles that used air-cooled engines. The Mercedes-Benz radiator and coolant hoses are made of a reinforced polymer that was designed specifically to withstand the temperature variations your engine produces. This way they can have an extended life span cooling your engine in all conditions. In time the radiator and coolant hoses will show some weakness from being exposed to the temperature variations the engine exposes them to. The common indication of this weakness on your Mercedes-Benz cooling system is the expansion in the circumference of one or more of the radiator or coolant hoses. An inspection under the hood can reveal if this bubbling or blistering effect is occurring. The easiest part of the inspection of the coolant hoses is the upper radiator hose. This is attached to the upper portion of the radiator and to the exit port on the engine. It is at these connections where the expansion of the hose generally occurs since the coolant is at its hottest. This expansion is the thinning of the walls of the hose and is then susceptible to causing a leak of coolant on your Mercedes-Benz car. When this is noticed, the replacement of both the radiator hoses is recommended. You never want to wait until a leak occurs that might possibly increase the chances of the engine overheating while you are using your vehicle in your travels. That means you will become stranded on the road.