Car is making bubbling/ boiling noise when i turn it off but not smoking nor do i see any leaks. Just recently changed raditor and the thermostat and changed the water pump couple months ago!

1 Answer 1


Boiling coolant suggests that the cooling system a) isn't holding pressure, or b) isn't full, and/or c) isn't cooling.

a) could be caused by a faulty radiator cap or coolant overflow tank cap, or a leak in the cooling system that you haven't seen. b) could be caused by not filling the cooling system completely, so that air remains inside; some cars require filling in non-intuitive ways. c) could be caused by a water pump failure (even new pumps fail), a failure of the pump's drive belt to actually drive the water pump shaft, a clogged radiator, and/or a failed thermostat.

  • Also the feedback line of the fuel system
    – Martin
    Nov 25, 2017 at 19:34
  • I suppose that's possible, as the fuel system is (should be, anyway) filled with fluid. But if the motor runs reasonably well, the fuel system won't have air in it and won't bubble or boil. Nov 25, 2017 at 19:55

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