[Cocacolakidd]

The normal operating temp should be around the mid mark on the temp gauge - If the motor is running cooler you will not get as good mileage/combustion - So your mechanic did you a favor there (Or so it seems). See how it is on a warm/hot day in traffic as this would be the only difference if there it gets over to or close the limit.

A thermostat there is only to help the motor to warm up faster, and once the motor is at operating temp the thermostat is no longer in play. The thermostat will help keep the motor in the operating range.

There is also a Fan switch thermostat that can be changed for different temps - both of the thermostats (Fan switch and water pump thermostat) should be matched for optimum operation.