You may find your GMC thermostat located on the top of your engine, in the outlet that leads to your radiator, or near the radiator hose inlet toward the bottom of your engine. No matter where your GMC thermostat is located, it is a small but important component of your car that you should be familiar with. Basically, a GMC thermostat is a paraffin based, temperature-sensitive valve that operates by opening or closing, depending on the temperature of your coolant. The GMC thermostat regulates your engine's cooling system and temperature control by blocking coolant (closing) when the engine is cold, and allowing coolant to flow (opening) as the engine warms up. The valve on your GMC thermostat opens more or less depending on how hot the coolant flowing through it has become. A faulty GMC thermostat can cause a multitude of problems. If your GMC thermostat is stuck open, it can result in low heater output, poor fuel economy, or overheating. Closed or completely open GMC thermostats cause knocking or pinging during acceleration as well as overheating. If your GMC thermostat does not work right, your vehicle can fail an emissions test. Faulty GMC thermostats, if left unchecked, can cause complete coolant system breakdowns. Your GMC thermostat should be replaced at least every two to three years and whenever it is not working to top capacity. When it's time to replace your GMC thermostat, make sure you purchase the thermostat that is right for your vehicle's make and model, as the wrong GMC thermostat can also cause problems in your engine. You will find the GMC thermostat you need in our easy-to-navigate online catalogue, and you'll have it delivered fast through one of our convenient ordering options: through our toll-free order number or our secure online server.