How to Install a Heater Core in a Chevy Cavalier

Last Updated: December 17, 2020 References

Installing a heater core in a Chevy Cavalier refers to replacing the part of the car's heating system which controls the temperature. Although it is a fairly involved process, it is not too complicated, so anyone with a little automotive know-how can accomplish this repair on their own. Follow these steps for how to install a heater core in a Chevy Cavalier.

Steps

1
Detach the negative battery line.^{[1]
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2
Lift the front end of your car and prop it up on jack stands.^{[2]
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3
Empty the radiator and loosen the seal to release the valve located under the front passenger's side.^{[3]
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4
Disconnect and remove the A/C heater drain tube from the firewall, if the car is equipped with air conditioning.
5
Detach the hoses from the heater core by releasing the clamps. After the cooling system has had a chance to completely empty, lower the jack.^{[4]
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6
Determine the access area for your vehicle.
- In the case of a Cavalier, you'll have to remove the entire instrument panel from the dashboard.
7
Examine the placement of the pipes surrounding the heater core once it is exposed.
8
Disconnect the heater core outlet.
9
Detach hoses that may still be installed at the heater core, loosen the bolt from the heater core cover and remove the cover.^{[5]
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10
Release the heater core mounting clamps and dislodge the heater core.
11
Wipe up any fluid which may have leaked.
12
Remove any seals, O-rings or other components that you can utilize on the new heater core.
13
Install these parts on the replacement heater core.
14
Position the replacement heater core and attach the mounting clamps.
15
Replace the heater core cover and reconnect the heater core outlet.
16
Reconnect any hoses that you can reach from the interior of the car.
17
Wait to reconnect the instrument panel until you've confirmed that everything is properly installed with no leaks.
18
Jack the front end up again and replace the jack stands.
19
Reconnect the remaining heater core hoses.
20
Replace the A/C heater drain tubes at the firewall.
21
Follow the owner's manual concerning the proper coolant combination and seal the valve and refill the radiator.
22
Remove the jack stands and let down the car. Reattach the negative battery cable.^{[6]
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23
Confirm that the hoses are properly reattached and that the radiator is both filled and capped.
24
Start the car and examine the area surrounding the heater core, checking for leaks.^{[7]
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25
Allow the car to run until the engine has reached full temperature, and then continue to look for leaks.^{[8]
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26
Start the heater and confirm proper function.
27
Replace the instrument panel after you've made any necessary hose reinstallation.
28
Confirm that the radiator is full according to the instructions in the owner's manual.
29
Verify that each of the removed components is correctly reinstalled.
30
Dispose of all of the fluids you have drained.^{[9]
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Community Q&A

Question

Where is the heater coil located?

Community Answer

On old cars and trucks it's located on the cowl (firewall) on the passenger side. In newer cars it's in a black box behind the radio or the glove box.
Question

I have changed my water pump, head gasket, valve cover gasket, the thermostat, and the radiator. Should I try changing the heater core?

Community Answer

Check the floor of the front passenger seat after you've driven the car; if it's wet then you absolutely need to replace the heater core. Another good sign is if your heater isn't blowing out hot air. If neither of these are happening but your car still seems to be loosing coolant, the problem might be one of the hoses attached to the heater core and not actually the heater core itself, or it could also be a hose somewhere in the engine. It's best to have your car properly diagnosed if you can't find the leak yourself.