I have bought some "Radweld" to put into my radiator to try and repair a small leak. I need it to circulate around the radiator and wonder if, by putting it in the coolant tank, this will happen. The chap in the shop said that some coolant tanks circulate while others act more as an overflow. Can anyone shed light on where it would be best to put the Radweld in for it to fully circulate around the radiator. Thanks