Here's a general overview. Specific steps and challenges will vary based on the exact configuration of your van. You should consult a repair manual specific to your year and model for precise instructions and diagrams. A Haynes or Chilton manual would be a valuable investment.
1. Preparation is Key:
* Safety First: Disconnect the negative battery terminal to prevent electrical shorts.
* Coolant Drainage: Completely drain the engine's cooling system. There will likely be drain plugs at the bottom of the radiator and engine block. Have a large container ready.
* Gather Tools: You'll need various tools including screwdrivers (Phillips and flathead), wrenches (metric), pliers, sockets, a drain pan, rags, a coolant flush, and possibly a sealant for the hoses. A shop vacuum can also be helpful for cleaning up spilled coolant. Consider using a torque wrench to ensure proper tightening of bolts and nuts after reassembly.
* Protect the Interior: Cover the dashboard and surrounding areas to prevent damage or coolant spills.
2. Accessing the Heater Core:
This is the most challenging part. It typically involves:
* Dashboard Removal (Partial or Full): This is usually necessary. You'll need to remove various trim pieces, possibly the steering column shroud, and potentially the entire dashboard. This process varies greatly between vehicles, so your repair manual is crucial here. Take pictures as you go to help with reassembly.
* Evaporator Core Removal (Possibly): The heater core is often located behind the evaporator core (part of the AC system). You may need to remove the evaporator core to access the heater core. This often requires disconnecting AC lines – take extreme caution here as AC systems contain high pressure refrigerant that can cause serious injury. Consider having this done by a professional if you are not experienced with AC systems.
* Heater Core Housing Access: Once the dashboard is partially or fully removed, you should be able to locate the heater core housing. This housing will need to be carefully removed.
3. Removing the Heater Core:
* Disconnect Hoses: Carefully disconnect the heater hoses from the heater core. Have rags ready to absorb any remaining coolant.
* Remove the Core: The heater core is usually held in place by several clips or bolts. Gently remove it from its housing.
4. Installation:
* Installation is the reverse of removal. Ensure all seals and gaskets are in good condition and replace any damaged ones. Pay close attention to hose routing and connections. It is crucial to properly align the core, as a crooked installation can cause problems.
* Refilling and Bleeding the Cooling System: After reassembly, refill the cooling system with the correct type and amount of coolant. Bleed the system to remove any air pockets that may have formed during the process. This is very important to prevent overheating.
Important Considerations:
* Repair Manual: This is absolutely essential. Generic instructions can't account for variations in your specific vehicle.
* Professional Help: If you are uncomfortable with any part of this process, especially dashboard removal and AC system work, consider taking your van to a qualified mechanic. The cost of professional repair may be less than the cost of damaging your van.
* Patience and Organization: This is a time-consuming project. Take your time, stay organized, and take plenty of pictures as you disassemble everything.
This is a general guide; the specific steps might vary depending on the exact model and configuration of your 1993 Chevy G20 van. Always consult a repair manual specific to your vehicle. Remember safety first!
