The cooling components of the Jaguar radiator and coolant hose are there to help maintain the temperature in your British engine at a constant level. They are made out of reinforced polymer, but in time will need replacing. The reason the radiator hoses on your Jaguar will wear out in time is due to the heat being absorbed by them. That disrupts the integrity of the polymer; ultimately weakening it. This weakening of the polymer will cause the Jaguar radiator and coolant hoses to lose their shape and begins to expand outward. This movement is accomplished by the walls of the hoses becoming thinner. In time, a leak will begin to spew coolant. To help prevent loss of coolant from a leaking radiator hose while on the road, a regular inspection of them and the other components under the hood should be conducted. The location of the most possible place for the coolant hoses to expand from heat degradation is where they are connected to the engine and radiator. This is where the heat is concentrated for the longest period of time under the hood of your Jaguar. If a leak is already suspected, the best time for an inspection is when the engine is hot and just turned off. This will build the pressure in your Jaguar coolant system to its maximum level. If you are looking for a leak in the radiator or coolant hose, this is the time it will look as a spray or fountain coming out. As the pressure is relived because of the leak, the fountain will get smaller until it no longer exists. Once the engine cools down, the damaged component can then be replaced.