Back flushing helps to remove corrosion build up from inside your radiator and restore optimal flow. To back flush your radiator you will first need to remove it from your car, details of how to do this are available in either the owners or the workshop manual.
Carry on reading at ….. http://www.classiccarhub.co.uk/articles/car-radiator-problems-overheating-back-flushing-coolant.html
MGB tips mods and maintenance 