Complete removal and replacement of the radiator on a 1966 Chevrolet Corvette with 327ci V8 engine, including coolant drain, hose disconnection, and transmission cooler line removal if equipped with automatic transmission.

Warnings

Tools required

Parts

• Radiator assembly × 1 — Use OEM specification or quality aftermarket equivalent for 327ci V8
• Upper radiator hose × 1 — Use OEM specification
• Lower radiator hose × 1 — Use OEM specification
• Hose clamps (worm drive style) × 4 — 1.5-2 inch diameter
• Radiator drain petcock × 1 — Use OEM specification if damaged
• Transmission cooler line sealing washers × 2 — Use OEM specification if equipped with automatic

Fluids

• DEX-COOL Extended Life (Orange) — 10 qt

Preparation

1. Ensure engine is completely cold to the touch (minimum 2 hours after last operation).
2. Park vehicle on level ground and engage parking brake.
3. Place wheel chocks behind rear wheels.
4. Disconnect negative battery cable to prevent accidental fan engagement.
5. Remove radiator cap slowly to release any residual pressure.
6. Position large drain pan underneath radiator drain petcock location.
7. Have replacement radiator, hoses, clamps, and coolant ready before beginning disassembly.

Procedure

1. 1

   Drain cooling system
   Locate the radiator drain petcock on the driver's side lower corner of the radiator. Open the petcock by turning counterclockwise by hand. Allow coolant to drain completely into the drain pan (approximately 10 quarts). If petcock is seized or damaged, disconnect the lower radiator hose instead. Once drained, close petcock hand-tight.
   Torque spec

   Drain Petcock5 Nm (4 lb-ft)
2. 2

   Disconnect upper radiator hose
   Locate the upper radiator hose connection at the top of the radiator on the passenger side. Using pliers, compress and slide the hose clamp back approximately 2 inches away from the radiator neck. Twist the hose gently to break the seal, then pull firmly to remove from the radiator. Some residual coolant will drain; have a shop rag ready. Inspect hose for cracks or deterioration and replace if necessary.
3. 3

   Disconnect lower radiator hose
   Access the lower radiator hose connection at the bottom of the radiator on the driver's side. Using pliers, compress and slide the hose clamp back approximately 2 inches. Twist and pull the hose from the radiator outlet. Additional coolant will drain; ensure drain pan is positioned correctly.
4. 4

   Disconnect transmission cooler lines (automatic transmission only)
   If equipped with automatic transmission, locate the two transmission cooler lines entering the radiator on the driver's side tank. Using a flare nut wrench to prevent rounding, loosen the cooler line fittings by turning counterclockwise. Expect transmission fluid to drain from the lines (approximately 0.5-1 quart). Cap the lines immediately with rubber caps or plug with clean rags to prevent contamination and further fluid loss. If the original sealing washers are damaged or compressed, replace them during reassembly.
5. 5

   Remove radiator shroud (if equipped)
   The 1966 Corvette may have a fan shroud attached to the radiator. Remove the 4 shroud mounting screws using a screwdriver or socket. Carefully lift the shroud upward and rearward, maneuvering it over the fan blades. Set aside for reinstallation. Take care not to damage the fan blades during shroud removal.
6. 6

   Remove radiator mounting hardware
   The radiator is secured by 2 upper mounting bolts or brackets attached to the radiator support. Locate these bolts at the top corners of the radiator. Using a socket wrench, remove both upper radiator mount bolts. The lower portion of the radiator sits in rubber cushion mounts and does not require bolt removal. Keep hardware organized for reinstallation.
7. 7

   Remove radiator from vehicle
   Carefully lift the radiator straight upward out of the engine compartment. The radiator will clear the fan assembly when lifted vertically. Take care not to damage the radiator core fins on the fan blades or surrounding sheet metal. The radiator is moderately heavy (approximately 15-20 pounds when empty); use proper lifting technique. Once clear, set the radiator on a protected work surface.
8. 8

   Clean and inspect mounting area
   With the radiator removed, inspect the radiator support and lower mounting cushions for damage, rust, or deterioration. Clean the mounting surfaces with a wire brush and shop rags. Check that both lower rubber radiator cushions are present and in good condition; replace if cracked or compressed. Inspect the fan blades for damage or excessive play in the water pump bearing.
9. 9

   Prepare new radiator for installation
   Unpack the new radiator and inspect for shipping damage. Verify that the drain petcock is installed and hand-tight. If the radiator does not include a drain petcock, install one now. Transfer any brackets or fittings from the old radiator to the new unit if necessary. Ensure transmission cooler line ports are clear of debris if equipped with automatic transmission.
   Torque spec

   Drain Petcock5 Nm (4 lb-ft)
10. 10

    Install new radiator
    Carefully lower the new radiator into the engine compartment, aligning the lower mounting tabs with the rubber cushions in the radiator support. Ensure the radiator sits fully into both lower cushions. Align the upper mounting holes with the radiator support brackets. Install the 2 upper radiator mounting bolts and tighten to specification using a torque wrench. Do not overtighten, as this can damage the radiator tanks or mounting ears.
    Torque spec

    Radiator Mount Bolts12 Nm (9 lb-ft)
11. 11

    Reinstall radiator shroud (if equipped)
    Position the fan shroud over the fan blades and align with the mounting holes on the radiator. Install the 4 shroud mounting screws and tighten securely with a screwdriver. Verify the shroud does not contact the fan blades at any point by manually rotating the fan through a complete revolution.
12. 12

    Connect transmission cooler lines (automatic transmission only)
    If equipped with automatic transmission, install new sealing washers on the transmission cooler line fittings. Thread the cooler lines into the radiator ports by hand to prevent cross-threading. Once hand-tight, use a flare nut wrench to tighten the fittings to specification. Do not overtighten, as this can strip the radiator tank fitting threads.
    Torque spec

    Transmission Cooler Lines25 Nm (18 lb-ft)
13. 13

    Connect lower radiator hose
    Slide a new hose clamp onto the lower radiator hose (if replacing hoses). Push the hose firmly onto the radiator outlet until it seats against the bead on the radiator neck. Position the hose clamp approximately 0.5 inches from the end of the radiator neck. Tighten the clamp to specification using a screwdriver or nut driver. Ensure the clamp is positioned over the bead to prevent hose blow-off under pressure.
    Torque spec

    Upper/Lower Hose Clamps3 Nm (2 lb-ft)
14. 14

    Connect upper radiator hose
    Slide a new hose clamp onto the upper radiator hose (if replacing hoses). Push the hose firmly onto the radiator inlet until it seats against the bead. Position the hose clamp approximately 0.5 inches from the end of the radiator neck. Tighten the clamp to specification. Verify both hoses are routed without kinks or contact with moving components.
    Torque spec

    Upper/Lower Hose Clamps3 Nm (2 lb-ft)
15. 15

    Fill cooling system and bleed air
    Using a funnel, slowly pour conventional ethylene glycol coolant (green) mixed 50/50 with distilled water into the radiator filler neck. Fill until coolant reaches the bottom of the filler neck. Allow time for coolant to settle and air to escape. Start the engine with the radiator cap off and allow it to reach operating temperature (approximately 10 minutes). As the thermostat opens, the coolant level will drop; add coolant as needed to maintain level. Watch for coolant circulation in the radiator and verify both radiator hoses become hot. Once the engine reaches full operating temperature and the upper hose is hot, install the radiator cap. Check coolant level in the overflow reservoir and fill to the COLD mark.
16. 16

    Check for leaks and test drive
    With the engine at operating temperature, visually inspect all hose connections, the radiator drain petcock, and transmission cooler lines (if equipped) for signs of leakage. Check the area under the vehicle for coolant drips. Reconnect the negative battery cable. Test drive the vehicle for 10-15 minutes, allowing the engine to reach full operating temperature under normal driving conditions. Monitor the temperature gauge for normal operation (typically 180-195°F). After the test drive, recheck all connections for leaks and verify coolant level.

Reassembly

1. Torque all fasteners to specification using a calibrated torque wrench.
2. Replace all hoses and clamps if they show signs of age, cracking, or deterioration.
3. Use only DEX-COOL Extended Life coolant (orange) as specified; do not mix with conventional green coolant.
4. If equipped with automatic transmission, check transmission fluid level after test drive and add Dexron III ATF as needed to compensate for cooler line loss.
5. Keep all old coolant contained for proper disposal at a recycling facility.

Verification

• Engine reaches and maintains normal operating temperature (180-195°F) without overheating.
• No coolant leaks visible at radiator hoses, drain petcock, or transmission cooler lines after test drive.
• Both radiator hoses become hot during engine warm-up, indicating proper coolant circulation.
• Coolant level remains stable in radiator and overflow reservoir after cooling down from test drive.
• Temperature gauge reads in normal range during idle and highway driving conditions.
• If equipped with automatic transmission, transmission fluid level is correct and no leaks are present at cooler lines.
• Fan shroud (if equipped) does not contact fan blades during operation.

More procedures for this vehicle