Using the new pump, you are able to determine the size of its large nut. It is either 34 or 36mm across the flats. Using a flat piece of metal, make a flat spanner with a length long enough to extend out of fan blades to fit the nut. With the 'spanner' on the nut and with a engineers hammer, strike the improvised spanner to undo the nut. The inertia of the assembly allows it to come undone. Viscous couple spanners to do exactly the same are available here in the UK for around £5 ($10 ?). Use a dab of Locktite when fitting the new pump, impacting it in the other direction to tighten it.
In a workshop with an air chisel, they can be undone by a couple of short bursts aimed at an angle to the nut.

Removing a Viscous Fan without the serpentine belt (1998 Land Rover Discovery)
I have a 2011 Suzuki SX4 Crossover AWD with MT.  Sometimes when I start it up, begin moving forward, or quickly decelerate I can hear what sounds like water (or some other liquid) moving from one place to another (can't quite tell where) under the dash or maybe just behind the firewall.  I took it to the Suzuki service center (almost 2 hour drive from my home), and they told me that the A/C coolant was low.  They refilled it and sent me on my way.  However, I still hear the sloshing sound behind the dash.  Does anyone have any ideas on what this might be?  Thanks.

ADDITIONAL INFO

I've recently noticed that when this "running water" sound occurs that it is more prominent when the engine is running faster (e.g. during acceleration).  This leads me to believe maybe this has something to do with the water pump, or some other liquid pump, that is run by the engine and not moving enough liquid to fill the pipe, hence a sloshing / running water sound.
