How to Replace the Heater Core in a Saturn

by Jin Machina

The heater core in your Saturn converts cool air into warm air by utilizing already heated coolant. The heater core has fins for air to pass through. It also has water tubes to let warm coolant cycle in and out. This process causes the air to heat as it blows into the passenger compartment. When replacing your Saturn's heater core with a new one, look for the correct specifications in depth, height, width, and diameters to the inlet and outlet ducts.

Removing The Heater Core

Disconnect the negative cable from the Saturn's battery.

Drain the coolant mix out of the cooling system. If the coolant mix is still good, save it for when it is time to refill the system. Otherwise dispose of it properly.

Remove the heater hose coming out of the thermostat housing behind the engine block on the 4-cylinder engine. This hose is connected to the heater core pump on V-6 engines. Drain any additional coolant mix.

Remove both heater hoses from the firewall-heater/air conditioner housing by squeezing the tabs on the locking couplers and pulling.

Take out the right console extension inside the passenger compartment by sliding it back.

Use your flathead screwdriver to pry the tabs on the heater pipe clamps. Remove the clamps from the couplers, then remove the pipes from the heater core.

Unscrew the heater core strap-mounting screw. Move the strap to the side.

Firmly grasp the heater core and pull it out of its housing.

Installing The New Heater Core

Install the new heater core into the housing.

Position the heater core strap and tighten the mounting screw.

Place the new rubber O-rings on the pipes. Fit the pipes back into the core's appropriate inlet and outlet tubes. Install the clamps on the couplers.

Slide back the right console extension.

Install both heater hoses back onto the firewall-heater/air conditioner housing.

Refit the heater hose back onto the thermostat housing behind the engine block for 4-cylinder engines. For V-6 engines, refit the heater hose back onto the heater core pump.

Refill the coolant system with the coolant mix.

Re-connect the negative cable on the battery.

Turn on your car and test the heater.


  • Inspect for any cracked or damaged hoses, pipes and other components. Replacing a heater core is a good opportunity to examine other parts of your Saturn.


  • Make sure the engine has cooled before starting the repair process.
  • When working around the airbag, always deactivate the airbag system. Sudden deployment of the airbag can result in bodily injury.

Items you will need


About the Author

Jin Machina began writing professionally in 2010. His main writing interests are film, literature, boxing and martial arts, automotive and performing arts. Machina has a Bachelor of Arts from the University of Washington, where he completed two majors: anthropology and comparative history of ideas, a discipline focused on culture, literature and the self.

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Photo Credits

  • car heater vent image by robert mobley from Fotolia.com