yea its pretty normal on some of our cars. it is annoying though.
you should go to autozone, get them to look for codes, its free.
waterpump you would have known about by now, car would have shut off.
thermostat will fail open, and leave a code without notifying on your dash at all.
my fan is loud as shit when the AC is on and it is hot out. if it isnt hot out, then the fan wont kick in.