When you pull the pump please take some pictures. I would like to see what the pump looks like.
I would also like to see what the fan looks like. I have a pretty big fan and I would like to see yours and the shroud.
I also found this the other day. Looks cool and is a great diagnosis tool. I would get the Chevy one as the Pontiac one looks too big for no good reason..
http://www.coolviewthermostat.com/
Dave