A cars radiator is a central part of the engines cooling system. Responsible for removal of heat from the engine coolant, the radiator system cools the liquid by allowing fresh external air to pass over a network of thin pipes, losing heat to the atmosphere.
Driven by the water pump the coolant circulates around the cooling system travelling through the engine and out via hoses or pipes to the radiator. The radiator acts as a heat exchange removing unwanted heat from the coolant before passing it back to the engine where it then runs back around the system.
The radiator top hose connects the engine to the upper part of the radiator bringing heated coolant from the block to be cooled as it passes through the radiator. The top hose is generally made of rubber or silicone hose although can also include metal sections on some vehicles.
The radiator top hose can usually be seen inside the engine bay from above, running between the engine and the top side of the radiator.
Due to the extremes in temperature and exposure to road grime and debris the radiator top hose is prone to perishing over time. If fitment of a new top hose is necessary, it’s essential that any coolant loss is replaced.