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How to Replace a 2003 Elantra Thermostat

by Russell Wood

The thermostat in a 2003 Hyundai Elantra is mounted to the engine block and acts as a regulator for the coolant in the cooling system. The thermostat makes sure that the coolant flows when it has to, and stays still when it doesn't. If the thermostat sticks open or closed, then the coolant won't be able to flow, and the engine will overheat. If you notice your engine temperature gauge rising higher than normal, you may want to replace your thermostat.

Let the engine cool down for a few hours. Put the drain pan on the ground, just underneath the radiator. Loosen the valve on the bottom of the radiator using your hands and allow a gallon of coolant to empty into the radiator.

Unbolt the thermostat housing from the engine using the 3/8-inch ratchet and socket. Pull the thermostat housing up off of the engine block and take out the thermostat and the thermostat gasket.

Install a replacement thermostat gasket and thermostat in the housing and then bolt it to the engine with the 3/8-inch ratchet and socket.

Remove the radiator cap. Fill the radiator with the pre-diluted coolant.

Warning

  • Hot coolant can cause serious injury, so make sure to let the engine cool down prior to working on the thermostat.

Items you will need

About the Author

Russell Wood is a writer and photographer who attended Arizona State University. He has been building custom cars and trucks since 1994, including several cover vehicles. In 2000 Wood started a career as a writer, and since then he has dedicated his business to writing and photographing cars and trucks, as well as helping people learn more about how vehicles work.

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