Before looking at the thermostat for cooling issues, take a look at the coolant level, drivebelt tension, and temperature gauge. To replace, detach the negative battery cable and completely drain the system. Also, disconnect the cooling fan switch, and detach the hose as well as the old hose. Remove the old thermostat and gasket. For installation, Install a new gasket and thermostat, make sure the air bleed faces up and the spring end is going towards the engine.