Disclaimer: This information is for general guidance only. I am not responsible for any damage to your vehicle or personal injury resulting from attempting this repair.
Steps (General Outline - Consult a Repair Manual for Specifics):
1. Preparation:
* Disconnect the battery: This is crucial to prevent electrical shorts.
* Gather tools: You'll need various wrenches (metric), sockets, screwdrivers (Phillips and flathead), a coolant recovery system or large container, a new heater core, pliers, possibly a flush tool for the cooling system, and potentially a shop manual specific to your vehicle.
* Drain the coolant: Locate the drain valve on the engine block and radiator (refer to your repair manual). This is crucial to avoid a mess.
* Protect your work area: Use drop cloths to protect your vehicle's interior and floor.
2. Dashboard Removal (Most Challenging Part): This is the most time-consuming and intricate step. You will likely need to:
* Remove the steering wheel (requires specialized tools and knowledge).
* Remove the instrument panel and various trim pieces. This involves many screws, clips, and potentially disconnecting electrical connectors.
* Remove the glove box.
* Disconnect the HVAC system components and ducting.
3. Heater Core Access: Once the dashboard is partially or fully disassembled, you'll be able to access the heater core. Its location varies slightly depending on the specific model and trim level. Your repair manual will show the exact location and how to reach it.
4. Heater Core Removal:
* Disconnect the heater core hoses. Have rags ready to absorb the remaining coolant.
* Carefully remove the heater core from its housing. This may involve removing the HVAC case itself.
5. Heater Core Installation:
* Install the new heater core, ensuring a proper seal.
* Reconnect the heater hoses.
6. Reassembly: This is the reverse of the disassembly process. Take your time and carefully reconnect all electrical connectors, HVAC components, and trim pieces. Reinstall the dashboard components.
7. Refill and Bleed the Cooling System:
* Refill the cooling system with the correct type and amount of coolant (consult your repair manual).
* Bleed the air out of the cooling system (this is crucial to prevent overheating). Consult your repair manual for the proper bleeding procedure.
8. Test: Start the engine and check for leaks. Run the heater to ensure proper functionality and to check for leaks again.
Why you should consider a professional:
* Complexity: The dashboard removal alone is a daunting task for most DIYers.
* Specialized Tools: Some tools needed for this job are not commonly found in home toolkits.
* Potential for Damage: Incorrect disassembly or reassembly can lead to damage to electrical components, the dashboard, or the HVAC system.
* Time Commitment: This repair can take several hours, even for experienced mechanics.
Strongly recommended: Obtain a repair manual specific to your 1999 Ford Expedition. This will provide detailed diagrams, step-by-step instructions, and torque specifications necessary for a successful repair. A Haynes or Chilton manual can be helpful resources. Visual guides (YouTube videos) can be helpful supplements, but always prioritize the information in your repair manual.
