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Cooling System - Houston's Premier Auto Repair Facility

​​Cooling System Home Page > Parts of the Cooling System > Radiator Cap Replacement


The radiator cap seals the coolant or antifreeze inside the cooling system. The cap has two valves - one for allowing coolant to escape the system when the temperature or pressure gets to high, and another that allows coolant to be sucked back into the system from the coolant reservoir when the system is low. When the spring in the radiator cap becomes weak, the coolant fluid is able to escape from the cooling system sooner than the ideal pressure. This lower pressure level also results in the coolant boiling at a lower temperature.


The radiator cap allows coolant to escape to an external reservoir when coolant pressure becomes too high.


Radiator cap pressure capability is easily tested using a cap tester, and the cap should be replaced whenever the spring becomes weak.


















Have your vehicle cooling system checked by ASE Certified Technician in Car Cooling. Schedule service today to visit our repair facility on the southwest side of Houston.