Cooling Fan Motor

Replacement of the engine cooling fan motor on a 1966 Chevrolet Corvette 327ci V8, including removal of shroud and fan blade assembly.

Warnings

Tools required

Parts

• Cooling fan motor × 1 — Use OEM specification
• Fan motor mounting gasket or seal (if equipped) × 1 — Use OEM specification

Fluids

• DEX-COOL Extended Life (Orange) — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Allow engine to cool completely for at least 2 hours after last operation.
3. Disconnect negative battery cable to prevent electrical short or accidental fan motor activation.
4. Place drain pan under radiator to catch coolant spillage during disassembly.

Procedure

1. 1

   Drain coolant from radiator
   Open the radiator petcock valve at the bottom of the radiator on the driver side and drain approximately 2 quarts of coolant into the drain pan. This prevents excessive coolant loss when removing components. Close petcock when level drops below the fan motor mounting area.
2. 2

   Remove upper radiator hose clamp
   Loosen the upper radiator hose clamp at the radiator using a screwdriver or socket. Slide the clamp back along the hose away from the radiator neck. Gently twist and pull the hose off the radiator to provide clearance for fan shroud removal.
3. 3

   Remove fan shroud mounting bolts
   Remove the 4 bolts securing the fan shroud to the radiator support. These are typically 7/16" hex head bolts located at the corners of the shroud. Lift the shroud up and back slightly, resting it on the fan assembly, but do not remove it completely yet.
4. 4

   Remove fan blade assembly from water pump
   Using a fan clutch wrench or large adjustable wrench, loosen the fan clutch from the water pump hub by turning counterclockwise (standard right-hand thread). Support the fan blade assembly with your other hand to prevent it from falling. Once loose, thread the clutch off completely and carefully remove the fan blade and clutch assembly as a unit. Set aside in a safe location.
5. 5

   Remove fan shroud completely
   With the fan blade assembly removed, lift the fan shroud up and out of the engine compartment. The shroud should now have clearance to be removed without obstruction.
6. 6

   Disconnect fan motor electrical connector
   Locate the electrical connector for the cooling fan motor. On 1966 Corvettes, this is typically a 2-wire connector near the radiator support. Press the retaining tab and pull the connector apart to disconnect power from the fan motor.
7. 7

   Remove fan motor mounting bolts
   Remove the 3 bolts securing the cooling fan motor to the fan shroud or radiator support bracket. These are typically 3/8" or 10mm hex head bolts. Note the position and orientation of any spacers or washers for reinstallation.
8. 8

   Remove old fan motor
   Carefully extract the fan motor from its mounting position. Inspect the mounting surface for corrosion or debris and clean with a wire brush if necessary. Check the condition of any mounting gasket or seal.
9. 9

   Install new fan motor
   Position the new cooling fan motor into the mounting location, ensuring proper alignment with mounting holes. If equipped with a mounting gasket or seal, install it between the motor and shroud. Thread in the 3 mounting bolts finger-tight, then tighten evenly in a star pattern to secure the motor firmly without overtightening.
10. 10

    Reconnect fan motor electrical connector
    Reconnect the electrical connector to the new fan motor, ensuring it clicks into place securely. Verify the connector is fully seated and the retaining tab is engaged.
11. 11

    Reinstall fan shroud
    Position the fan shroud back into place over the radiator, aligning the mounting holes with the radiator support. Install the 4 shroud mounting bolts finger-tight but do not fully tighten yet.
12. 12

    Reinstall fan blade assembly
    Carefully position the fan blade and clutch assembly onto the water pump hub. Thread the fan clutch onto the hub clockwise (standard right-hand thread) by hand until snug. Use the fan clutch wrench to tighten securely, typically 15-20 ft-lbs of torque applied by feel (do not overtighten). Verify the fan blade has proper clearance from the shroud and radiator in all positions by rotating it by hand.
13. 13

    Final tighten fan shroud
    With fan blade assembly installed and clearances verified, fully tighten the 4 fan shroud mounting bolts securely. Ensure the shroud is properly positioned and not contacting the fan blade at any point of rotation.
14. 14

    Reconnect upper radiator hose
    Slide the upper radiator hose back onto the radiator neck, ensuring it is fully seated. Position the hose clamp over the connection point and tighten securely with a screwdriver or socket.
15. 15

    Refill coolant and check system
    Refill the radiator with DEX-COOL Extended Life coolant to the proper level. Reconnect the negative battery cable. Start the engine and allow it to reach operating temperature while monitoring coolant level and checking for leaks. Verify the new cooling fan motor activates properly when the engine reaches normal operating temperature.

Reassembly

1. Ensure all electrical connections are secure and properly routed away from moving parts and heat sources.
2. Double-check fan blade clearance to shroud and radiator after all components are installed.
3. Top off coolant level after engine reaches operating temperature and allow system to burp air.

Verification

• Start engine and let idle until cooling fan activates automatically, confirming new motor operates correctly.
• Check for unusual vibration or noise from the fan motor during operation.
• Verify no coolant leaks around radiator hose connections or petcock valve.
• Confirm fan blade rotates freely without contacting shroud or radiator at any point.
• Test drive vehicle and monitor temperature gauge to ensure cooling system maintains normal operating temperature.

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