How to Change the Thermostat in a Hyundai Sonata

The Hyundai Sonata is a mid-size sedan known for generous headroom, a big back seat and a huge trunk. A long list of standard options, lots of safety features, a terrific warranty program and a low price shot the Sonata to the top of buyers' list in 1989. The 1999 Sonata was the result of three rounds of improvements, which has better engines and significant upgrades in ride quality. This do-it-yourself installation of a new thermostat, is for models produced between 1999 and 2003.

Instructions

1

Allow the engine to cool completely before servicing the vehicle. Disconnect the negative battery cable. Drain the coolant in the radiator to a level that is below the thermostat.

2

Remove the coolant outlet fitting and its gasket. Discard the gasket. Clean any dirt or gasket material from the outlet fitting.

3

Lift out the thermostat, noting its orientation. Install the new thermostat in the same position as the old one. Replace the coolant outlet fitting with a new gasket.

4

Fill the cooling system with the appropriate type and amount of coolant. Reconnect the negative battery cable.

5

Start the engine and allow it to run until it is warm. Check for leaks and proper operation. Check the level of the coolant in the overflow tank and add coolant as necessary.