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Radiator Hose Information

Radiator Hoses
The coolant and heater hoses are a cooling system’s weakest structural components. They’re made of flexible rubber compounds to absorb vibration between the engine and the body’s firewall. Designed to hold coolant under high pressure, radiator hoses are also subject to fluctuating extremes of heat and cold in addition to atmospheric ozone which attacks the rubber compounds.

The most damaging cause of hose failure, electrochemical degradation (ECD),and it isn’t easy to detect. ECD can attack the hoses from the inside, causing tiny cracks. Acids and contaminants in the coolant can then weaken the internal material that reinforces the hose. Eventually, pinholes can develop or the weakened hose may rupture from heat pressure or constant flexing.

Some basic maintenance can help prevent coolant hose failure. First, check the white coolant-recovery tank often to ensure a proper fluid level. Marks on the tank indicate the proper level for when the engine is cold or hot. If the tank is low after repeated fillings, suspect a leak. Also check for white, light green, or pink coolant tracks in the engine bay, which is residue left from leaking coolant.

When the engine is cool, squeeze the hoses with your thumb and forefinger near the clamps, where ECD most often occurs. Feel for soft or mushy spots. A good hose will feel firm yet pliant. Flush and replace the coolant according to the owner’s manual. Clean coolant is less likely to support ECD.

Note also that the upper radiator hose fails more often than any other hose, followed by the water pump bypass hose and the outlet heater hose from the engine to the heater core.