I have noticed increased activity in the cooling system. Some days the temps run hotter for longer periods and take longer to cool down from the hotter readings. While the temps are not "over heated" they will become hotter and will fluctuate considerably independent of driving conditions .. then there are days when temps are predictable and consistent with driving conditions. Could this be an early indication of a water pump failure? It'* an 07 Grand Prix GXP 77,800 miles. Level of coolant is as it should be and there has not been the need to add any . No troubles of this nature to note. What might be causing operating temps to fluctuate one day then not so much on another day? Thank you for your comments .

I can't speak to that particular engine, but usually something else is to blame, whether it be clogging in the cooling system, a fan not pulling air properly, a buildup of trash between the condenser and radiator, buildup on the condenser, or even a bunch of bent fins on the radiator or condenser. Even something like an air pocket in the cooling system could affect it. That is even assuming the reading you are getting is correct (wonky GM Gauge syndrome?).

Usually, water pumps are mechanical, and the only way they could falter in their flow rate is if they are not spinning the proper speed (belt slip) or if the impeller blades are damaged or missing.

Water pump failure will not create intermittent issues. Usually the first sign of a failing water pump is coolant leakage from the weep hole. I don't think the problem is a thermostat, as they typically fail in the open position and cause the engine to run cooler than normal, not hotter. Could be a defective temperature sensor, contamination on the cooling surface of the radiator, or coolant circulation issues.

I would start by thoroughly cleaning the radiator (use Simple Green), a complete flush of the cooling system, and fresh coolant. This might fix your problem, but even if they don't you have not wasted your money since these are good basic maintenance items.

Thank you both for your comments .. Yes the radiator flush is on the list of to do maintanence ..