Non-toxic coolant is sold at auto parts stores and requires proper disposal. This applies to 2006 and earlier models. For 2007 and later models, the engine coolant temperature sensor operates the temperature gauge. If the gauge is inoperative, check fuses first. If it shows excessive temperature, refer to Troubleshooting. If it indicates "Hot" on a cold start, disconnect the wire at the coolant temperature sender. If the gauge reading drops, replace the sending unit. If it remains high, the wire or gauge may be faulty. If the gauge doesn't respond after warming up the engine and checking fuses, the circuit or gauge may be faulty. To replace, drain the coolant, disconnect the wiring connector, remove the sending unit, install the new one, and refill the cooling system. Check for leaks and gauge function.