Well I'm glad you got it figured out. Today I figured out why my '98 Sentra 1.6 L GXE has been making a whistling noise or I guess a howling noise.... My factory water pump bearing is shot. 138K miles. I guess that's not bad to go that long before replacing! I did not seem to be losing any coolant and did not notice any coolant seeping through the weep hole. After the belt was off I spun the pulley and it was obvious the noise it made.
I spent the better part of 6 hrs tearing the water pump out, it is really hard to get the thermostat housing bolts (3-10mm) out. But after removing the engine support bracket bolts (3-14mm) I managed to gain some extra working room. I thought I would have to remove the power steering pump in order to get the thermostat housing loose. I was able to remove the two bolts (10mm & 12mm) from the power steering belt adjuster bracket. Once the two bolts are removed and the belt is removed the adjuster bracket can fall down out of the way to gain a bit more hand room. I used a variety of 1/4" drive extensions to remove the three thermostat housing bolts. I did no t remove the thermostat water outlet bolts (where the thermostat is contained). Also did not remove any hoses except for the small U shaped one that can be removed easy from the top side of the engine, (this hose was blocking the top two thermostat to water pump mounting bolts). Just separated the thermostat housing bolts where they attach directly to the water pump. Once I had the bolts out I was able to remove it by tapping on the thermostat housing using a long 1/2" drive extension and hammer. The pump removal was relatively easy after this. Installed the new water pump, belts, and new idler pulley while at it. Car is much quieter now! Hoping for another 100K miles!!
'05 Toyota Tundra Limited
''02 Toyota Avalon XLS
'98 Nissan Sentra GXE
'94 Nissan Hardbody XE, retired 2010 /I]