Heater Core Removal and Replacement – 2.5L NA

Overview

This procedure explains how to remove and replace the heater core in a Porsche 944 (8-valve engine variants). It’s a necessary process for resolving heater core leaks, blockages, or inefficient heating. Completing this task without dashboard removal saves significant time and effort.

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Tools Required

• Stubby Phillips head screwdriver
• Regular Phillips head screwdriver
• Small flat tip screwdriver
• Metric wrench (for battery negative terminal)

Step-by-Step Procedure

Step 1: Preparation and Access

1. Disconnect the negative terminal from the battery.
2. Drain the coolant system.
3. Remove the glove box to access the heater core area.
4. If equipped, disconnect the thermometer hose and remove the plastic air duct.

Step 2: Removal of Air Ducting

5. Remove the lower plastic duct secured by one screw.

6. Cut and remove the zip-tie securing wiring to the upper duct piece.

7. Remove the three screws holding the upper duct piece and remove it carefully.

Step 3: Removing the Heater Core

8. Place a container under heater core pipes to catch spilled coolant.
9. Use a screwdriver to carefully pry off the two retaining clips from the heater core pipes. Do not lose these clips.

10. Gently move vacuum elements and any obstructing items aside to gain clear access to the heater core.

11. Carefully start pulling the heater core out of its housing, avoiding contact with surrounding components.

12. You will encounter resistance from wire looms; undo and remove the plastic strap securing these wires to create more space.

13. Carefully maneuver wires while extracting the heater core. Expect some minor wire loom damage—avoid breaking insulation.

14. Fully remove the heater core from its housing.

Step 4: Installation

15. Installation is the reverse of removal. Ensure all components are reinstalled securely and correctly aligned.
16. Reconnect heater core pipe clips securely.
17. Refill and bleed the coolant system thoroughly.

Post Procedure Checklist

• Reconnect battery negative terminal securely.
• Ensure no coolant leaks around heater core pipes.
• Check heater function by running engine to operating temperature and verifying warm airflow.
• Inspect all disturbed wiring and ducts for secure reinstallation.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manual, Volume 1
• Youtube