Here's a general outline, but this is not a complete guide and specific steps might vary depending on the exact model and conversion modifications:
1. Preparation:
* Consult a Repair Manual: Obtain a factory service manual specific to your 1999 Ford E150 van. This is crucial for accurate procedures and torque specifications.
* Gather Tools: You'll need a wide array of tools, including various wrenches, sockets, screwdrivers, pliers, a coolant recovery system, a vacuum pump (to bleed the system), and possibly specialized tools for accessing the heater core.
* Safety Precautions: Disconnect the negative battery terminal. Wear safety glasses and gloves. Work in a well-ventilated area as you'll be working with coolant.
* Drain Coolant: Completely drain the engine's cooling system.
2. Accessing the Heater Core:
* Dashboard Removal (Likely): This is the most challenging part. You'll likely need to partially or completely remove the dashboard. This involves disconnecting various components – wiring harnesses, HVAC controls, etc. Take plenty of pictures and label everything meticulously as you disassemble. Some conversion vans may have custom dashboards, making this even more difficult.
* Access Panel (Possible, but less likely): Some vans might have an access panel behind the glove box or under the dash that allows easier access. Check your repair manual.
3. Heater Core Replacement:
* Disconnect Heater Core Hoses: Carefully disconnect the heater core hoses. Have containers ready to catch the remaining coolant.
* Remove the Heater Core: This will vary depending on your van's design. You might need to remove surrounding components (like the blower motor) to get to it. The core is usually held in place by clamps or screws.
* Install the New Heater Core: Carefully install the new heater core, ensuring it's seated correctly.
* Reconnect Heater Core Hoses: Reconnect the heater core hoses, ensuring they are securely attached and leak-free.
4. Reassembly:
* Reassemble the Dashboard: Carefully reassemble the dashboard and all related components. Refer to your pictures and labels. Double-check all connections.
* Refill Coolant: Refill the cooling system with the correct type and amount of coolant.
* Bleed the Cooling System: Use a vacuum pump or the "burping" method to remove air pockets from the cooling system. This is critical to prevent overheating.
* Test the System: Start the engine and check for leaks. Run the heater to ensure it's working correctly. Monitor the temperature gauge.
Important Considerations:
* Conversion Van Variations: The specific procedure will vary greatly depending on the conversion van's manufacturer and the modifications made.
* Professional Assistance: This is a complex job. If you're not comfortable with advanced automotive repair, it's strongly recommended to take your van to a qualified mechanic specializing in automotive HVAC systems. The cost of professional repair will likely be less than the cost of damaging your van during a botched DIY attempt.
This outline is a high-level overview. Without a repair manual specific to your van's model and conversion, attempting this repair could lead to significant damage. Always prioritize safety and consult a professional if you are unsure about any step.
