My 2003 Monte Carlo SS, 3.8L, has been overheating lately. When I took it the mechanic, he said it is my water pump, and suggests I replace the thermostat too. Is this recommended, or just a shotgun approach to correct my overheating problem?

 

Water pump, full flush, and replacing the thermostat is pretty standard. Good chance you have crud in your coolant system, and the thermostat is not where the cost is.

As long as you aren't losing coolant, I agree you should do it.