Here's a general overview of the process. This is NOT a substitute for a professional repair manual. Failure to follow proper procedures can lead to damage or injury.
1. Preparation:
* Safety First: Disconnect the negative battery terminal. Wear safety glasses and gloves. Work in a well-ventilated area.
* Gather Tools and Supplies: You'll need a variety of tools, including wrenches (metric), sockets, screwdrivers, pliers, a radiator drain pan, a funnel, coolant, new radiator hoses (often recommended), new radiator clamps, possibly a transmission cooler line wrench (if applicable), and possibly a torque wrench.
* Raise the Vehicle: Securely lift the van using jack stands. Never work under a vehicle supported only by a jack.
* Drain the Coolant: Locate the radiator drain petcock (usually at the bottom of the radiator) and carefully open it to drain the coolant into your drain pan. This can be messy, so be prepared.
2. Radiator Removal:
* Disconnect Hoses: Carefully disconnect the upper and lower radiator hoses. Have rags ready to absorb any remaining coolant. Take pictures before disconnecting hoses to help with reassembly.
* Disconnect Transmission Cooler Lines (if applicable): If your van has an automatic transmission, you'll need to disconnect the transmission cooler lines from the radiator. These may require special wrenches to avoid damaging the fittings.
* Disconnect Electrical Connections (if any): Some radiators have electrical connections (e.g., for a temperature sensor). Disconnect these carefully.
* Remove Radiator Support: This step will vary significantly depending on the van's design. You may need to remove screws, bolts, or clips holding the radiator support in place. The support may need to be partially or fully removed to access and remove the radiator.
* Remove the Radiator: Carefully remove the radiator. It might be heavy, so have assistance if needed.
3. Installation of the New Radiator:
* Install Radiator Support (if removed): Reinstall the radiator support if you removed it during the removal process.
* Install the New Radiator: Carefully position the new radiator in place.
* Reconnect Hoses and Transmission Cooler Lines: Reconnect the upper and lower radiator hoses, ensuring they are securely clamped. If applicable, reconnect the transmission cooler lines.
* Reconnect Electrical Connections (if any): Reconnect any electrical connections.
4. Final Steps:
* Fill with Coolant: Carefully fill the radiator with the correct type and amount of coolant (refer to your owner's manual). Use a funnel to avoid spills.
* Bleed the System: Start the engine and let it run for a few minutes to allow the coolant to circulate and bleed out any air pockets. Check the coolant level frequently and add more as needed.
* Check for Leaks: Inspect all connections for leaks.
* Lower the Vehicle: Carefully lower the vehicle from the jack stands.
* Dispose of Old Coolant Properly: Follow local regulations for disposing of used coolant.
Important Considerations:
* Professional Assistance: If you're uncomfortable with any part of this process, it's best to seek professional help from a qualified mechanic.
* Repair Manual: A repair manual specific to your 2003 Chevrolet 3500 Express van is crucial. It will provide detailed instructions, diagrams, and torque specifications.
* Coolant Type: Use the correct type of coolant specified in your owner's manual. Mixing different types can be detrimental.
This is a general guideline. The specifics of the radiator replacement will vary depending on your van's exact configuration. Always consult a repair manual before attempting this repair. Incorrect installation can lead to serious damage to your vehicle.
