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  • 07-27-2010, 07:59 AM

    No need to test cap

    The cap does not regulate the pressure so can not affect the operation of the cooling system, the pressure is a function of temperature versus volume of the coolant as the cooling system is a closed system.

    The cap does have an over pressure type of valve function but this is well above the normal operating pressures of the system. There is no need to test for this function as the pressure should never be reached.

    If the cap has no signs of coolant leaks from it then you know its working fine, all it does is pressure seals the expansion tank
  • 07-27-2010, 04:21 AM

    Coolant expansion tank cap, good or bad?

    I got the answers regarding thermostat and water pump. The next assignment, and question is regarding coolant expansion tank cap.
    How to test it, figure out when it's good and bad. 13 years old cap should be replaced or not? If it's sealed, it causes overpressure in the system and does not release the pressure, it does not hold the proper pressure and may overpressure the system. Without replacing not necessary parts, does anyone knows how to test it, if its good or not, it it holds the proper pressure and does not overpressure the system?

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