1. Clutch Fan: This is the most common type. The fan is attached to the water pump via a clutch assembly.
* Safety First: Disconnect the negative battery cable before starting any work on the cooling system. The system will be hot, allow it to cool completely before proceeding. Wear safety glasses.
* Identify the Clutch Fan: Look at the fan and water pump. If you see a visible clutch assembly (usually a spring-loaded mechanism) between the fan and the water pump, you have a clutch fan.
* Remove the Fan Shroud (if applicable): Many trucks have a fan shroud—a metal or plastic housing surrounding the fan. You'll likely need to remove this first. This typically involves removing a few screws or clips holding it in place.
* Remove the Fan Nut: Locate the large nut on the water pump shaft that secures the fan clutch. You'll likely need a wrench or socket that fits this nut. It might be very tight, so a breaker bar or impact wrench might be necessary. Important: Hold the water pump pulley firmly to prevent it from turning while you loosen the nut. Use a wrench or a special fan clutch holding tool to keep the pulley from spinning. If you don't have the tool, you might be able to use a strap wrench, but be careful not to damage the pulley.
* Separate the Fan Clutch and Fan: Once the nut is loose, the fan and clutch assembly should come off the water pump shaft. Sometimes they separate easily, other times the clutch might be stuck. If stuck, use a puller or carefully work it off.
2. Non-Clutch (Electric) Fan: This is less common on a 1997 GMC 1500 but possible.
* Safety First: As above, disconnect the negative battery cable. Let the system cool completely.
* Locate the Fan Mounting: Electric fans are usually mounted to the radiator or a bracket near the radiator, not directly to the water pump.
* Disconnect Electrical Connections: Unplug the electrical connector(s) that supply power to the fan motor.
* Remove Mounting Bolts/Clamps: Remove the bolts or clamps holding the fan to its mounting bracket.
* Remove the Fan: Carefully remove the electric fan.
Important Considerations:
* Rust and seized parts: Older vehicles often have rusted or seized components. Penetrating oil applied several hours before attempting removal can help.
* Special tools: You may need specialized tools like a fan clutch holding tool or a puller to remove the fan or clutch assembly. A good quality socket set and wrench set are essential.
* Water pump replacement: Since you're working on the water pump, it is often advisable to inspect its condition and replace it if necessary while you're already there. A failing water pump can cause serious engine damage.
If you're not comfortable with this task, it's best to take your truck to a qualified mechanic. Improper removal can damage the water pump or other components. Remember to consult a repair manual specific to your 1997 GMC 1500 for detailed diagrams and instructions.
