How to Change the Thermostat in a Toyota Corolla

More than 200,000 Americans, from high schools kids to retirees, purchase Toyota Corollas every year. Used-vehicle buyers looks for the eighth generation Corolla (1998 to 2002) because of its solid acceleration in a 1.8L engine, comfortable ride and outstanding quality and materials. This is a beginner level do-it-yourself project.

Things You'll Need

  • Mechanic's toolset, including a full socket set, wrenches and screwdrivers
  • Replacement thermostat, new or rebuilt
  • New gasket for thermostat
  • Remove the cover on the right side of the under-engine. Drain the engine coolant into a sealable container.

  • Take out the fan and the V-belt on the generator, then remove the generator assembly. Remove the two nuts that hold the water inlet in place and then pull the water inlet.

  • Lift out the thermostat and remove the gasket. Clean the gasket mating surfaces thoroughly of dirt and old gasket material.

  • Put a new gasket on the thermostat, then install the thermostat so that the jiggle valve is on top. Make sure the thermostat is set within 10 degrees to either side of the prescribed position.

  • Connect the water inlet and set the two nuts in place. Tighten the nuts to 8 foot pounds.

  • Set the generator assembly in place. Refill the engine with coolant. Start the engine and check for leaks. Replace the right side cover under the engine.