DII TD5. Not long after leaving home there was a strange noise at one point a sort of lowish frequency whine didn't last long a didn't happen again. The Car didn't seem quite right driving, a little down in power, tick over marginally higher than normal and hunting just a little bit.
Then after parking up doing a bit of shoping, pulling away from some lights there was a couple of loud bangs and clonks and something thumped the underside of the bonnet enough to make it move. Engine still running, no loss of power, no weird noises. Pulled over half thinking that an animal had taken cover near the nice warm engine or somthing. Leave engine running, open bonnet no sign of animal, no sign of any damage, no sign of any leaks. Just about to give up looking when I notice the fan blades are not going round and are not lining up with the curve of the cowl. Switch off, reach in and fan is completely detached from water pump(?). It has unscrewed itself and fallen off, fortunately without puncturing the radiator.
Now what would cause that? Surely the direction of rotation is such that it tightens the thing up? I could turn the big mounting nut on the fan unit with fingers after I lifted it out and it was still warm so I don't think the viscous unit has failed but if it has seized it may explain the poor running. With no fan the car does seem to be running smoother and better, engine temp is not rising above normal.