1. Disconnect the battery:
- Locate the battery.
- Disconnect the negative (black) terminal of the battery.
- Move to a well ventilated area and avoid direct ignition of the battery.
2. Drain the coolant:
- Locate the radiator drain plug usually at the bottom of the radiator and open it carefully.
- Position a large container underneath to collect the coolant.
- Allow the radiator to empty completely.
- Close the drain plug.
3. Remove the dashboard:
- Remove the steering wheel.
- Remove glove compartment.
- Remove all bolts and screws that may be present on the dashboard.
- This generally involves pulling parts on the bottom and sides.
- Pull out the top part of the dashboard and then the lower sections.
4. Locate and Remove the Heater Core:
- You should now be able to see the heater core, usually located behind the center of the dashboard.
- Remove any screws, nuts or bolts that hold it in place.
- Gently take the heater core, being careful not to spill any coolant.
5. Install the new heater core:
- Slide in the new heater core carefully into its place, making sure that it fits properly.
- If necessary, replace the O-ring or gasket that seals the heater core to prevent leakage.
- Securely fasten it with the replaced bolts and nuts.
6. Reattach the dashboard:
- Gently push the dashboard back to reconnect all the clips, then insert and secure the screws.
- Put back the steering wheel.
7. Refill the coolant and reconnect the battery.
- Refill the radiator with the proper amount of coolant mixture (Refer to the owner’s manual for the exact coolant type and quantity required).
- Turn the heater fan on to the maximum.
- Start the engine and run for several minutes with the heater on.
- Check the coolant level again and top up if needed.
It's important to note that this process can vary depending on the exact model and year of your Opel Astra, so it is recommended to refer to a vehicle specific repair manual or a professional for assistance.
