Seized viscous coupling input nut

I am having great difficulty in removing the viscous coupling and fan which I need to do to replace the timing belt. I have the correct land rover tools (LRT-12-093 and 094) but they will not shift the input nut. The nut flanges are now rounded so the spanner will not grip. Have tried the centre punch and cold chisel trick but still no movement. Would welcome any advice other then cut it off! Keith from Leicestershire.

welcome!

Thank You.

Heats always useful. Are you trying to undo it the right way? Which engine?

if you use a thickish flat pinch in the center of each flat and keep going round each one in turn eventually nut will unscrew by hand, knocking the edges off isnt the way to do it ,hitting in the center eventually stretches the nut

Getting any meaningful heat down on to the nut would be a bit tricky as the gap is not that wide and I dont want to damage either the fan pulley or the fan blades themselves - unless you can suggest otherwise. And yes I am aware its a LH thread and its a 300TDi.
Will have a go at attacking each flat with a small bladed chisel to see if that will work. Thanks. Any other suggestions would still be welcome

keith cowley said:

Getting any meaningful heat down on to the nut would be a bit tricky as the gap is not that wide and I dont want to damage either the fan pulley or the fan blades themselves - unless you can suggest otherwise. And yes I am aware its a LH thread and its a 300TDi.
Will have a go at attacking each flat with a small bladed chisel to see if that will work. Thanks. Any other suggestions would still be welcome

Click to expand...

a chisel will just destroy the nut but it would come undone if split a flat headed drift preserves the nut and still comes undone

Ok will have a go with a suitable drift. Not to bothered about destroying the nut as I have a new viscous coupling to go on as I'm not sure the current one is working properly. But anyway will give your suggestion a go. Thanks.