Wonder if anyone can help .. when i switch the ignition on and no matter how far i have drive, even switching the car on/off i got the buzzing noise which i believe is the coolent pumping round the engine to cool it down .. at the moment i dont get that noise anymore , is it supposed to come on all the time the car is switched off? or only when ive been driving hard? ive noticed this happening since ive had my dynatwist fitted ..