Hey all, for a while now I've had a problem where the needle for coolant temp in the standard cluster will dip from the normal level depending on if the engine is under load or if the car is going over bumps etc. The coolant level is pretty much full, and I've topped it up before now with no effect. When the car is stopped and there's no throttle what so ever, the needle always returns to the normal temperature position (just under half), so it can't be overheating. Range of movement can be from normal level all the way down to the bottom of the gauge. Never goes above. The waterpump is practically brand new, and the belt hasn't been slipping (no noise, alternator is fine etc), so what could it be? A bad earth or something that's loose (moving about with the car's movement), or a knackered temp sensor? Anyone had this before?