It Still Runs is the go-to destination for all things cars. From motors to radiators and everything in between, we've got you covered.


How to Change the Thermostat in a Saturn Ion

by Contributor

The Ion came on the scene in 2003 as Saturn's effort to capture young buyers. Despite unique styling and design and the solid power of a 2.2L engine, the Ion was discontinued in 2007, giving way to the Astra. The steps below detail the installation of a new thermostat in the Ion.

Remove the Thermostat

Step 1

Pull the negative battery cable from the terminal. Drain the engine coolant (see Warnings). Remove the bolts that hold the exhaust heat shield and then remove it.

Step 2

Raise the vehicle on a lift or secure supports. Release the coolant from the water pump drain plug. Collect the coolant into a suitable container.

Step 3

Loosen and remove the bolts that secure the thermostat housing. Lift off the thermostat housing and discard the O-seal.

Step 4

Take the water pipe from the water pump assembly, then remove the water pipe seals and throw them away.

Remove the inner thermostat sleeve. Lift out the thermostat assembly.

Install the Thermostat

Step 1

Position the thermostat cartridge into the housing. Align the cartridge tangs with the housing bolt holes to assure easy installation into the inner sleeve. Line up the notch on the inner sleeve and insert the sleeve into the housing.

Step 2

Put a new O-seal on the water pipe. Use a bit of silicon gel to lubricate the seals as needed. Set the water pipe into the water pump assembly.

Step 3

Fit the water feed O-seal by pushing it toward the water pump while twisting it gently so as not to damage or tear the O-ring.

Step 4

Place the thermostat housing cover on the water pipe. Set the new thermostat housing cover seal into the recess groove.

Step 5

Set the thermostat housing cover in place. Install the bolts to the cover and torque them to 89 inch pounds.

Step 6

Lower the vehicle. Install the exhaust heat shield and bolt it in place. Torque the bolts to 17 foot pounds. Make sure to close the radiator drain valve and the water pump drain.

Fill the engine with coolant. Attach the negative battery cable. Start the engine and test for leaks.


  • Dogs and cats will drink coolant left in open containers or on the floor and ingestion is usually fatal. Drain coolant into a sealable container. Reuse coolant unless it's contaminated or old and properly dispose of used coolant.

Items you will need

  • Mechanic's toolset, including a full socket set, wrenches and screwdrivers
  • Replacement thermostat, new or rebuilt
  • New gasket for thermostat

More Articles