Q: How to replace a thermostat in a cooling system for Chevrolet Cobalt,HHR,Saturn ION and Pontiac G5?
A: Before faulting the thermostat, check the coolant level, drive belt tension, and temperature gauge. To replace the thermostat, disconnect the battery's negative terminal and drain the coolant. Detach the hoses from the thermostat housing cover. Remove the thermostat and install a new gasket.