Radiator Hose - Lower

This procedure covers the removal and replacement of the lower radiator hose on a 1966 Chevrolet Corvette with the 327ci V8 engine, including coolant drainage and refill.

Warnings

Tools required

Parts

• Lower radiator hose × 1 — Use OEM specification or Gates 20881
• Hose clamps (worm-gear style) × 2 — 1.5 to 2 inch diameter range

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 apply parking brake
3. Place protective covering over front fender area to prevent coolant damage to paint
4. Locate radiator petcock drain valve on driver side lower radiator tank
5. Position drain pan under radiator drain valve

Procedure

1. 1

   Drain cooling system
   Open the radiator petcock drain valve by turning counterclockwise. The valve is located on the driver side of the radiator lower tank. Allow coolant to drain completely into the drain pan. If the petcock is seized or leaking, proceed to remove the lower radiator hose to drain the system.
2. 2

   Remove radiator cap
   Remove the radiator cap to allow air into the system and speed draining. This also ensures complete drainage from the lower hose.
3. 3

   Loosen hose clamp at radiator connection
   Locate the worm-gear hose clamp securing the lower radiator hose to the radiator outlet (lower radiator tank). Use a flathead screwdriver to loosen the clamp by turning the screw counterclockwise. Slide the clamp back along the hose away from the radiator connection, at least 3 inches.
4. 4

   Loosen hose clamp at water pump connection
   Locate the worm-gear hose clamp securing the lower radiator hose to the water pump inlet on the passenger side of the engine block. Use a flathead screwdriver to loosen the clamp by turning the screw counterclockwise. Slide the clamp back along the hose away from the water pump connection, at least 3 inches.
5. 5

   Remove lower radiator hose
   Grip the hose firmly near the radiator connection and twist while pulling to break the seal. Remove the hose from the radiator outlet. Repeat the twisting and pulling motion at the water pump inlet to remove the hose completely from the vehicle. If the hose is stuck, carefully use pliers to grip and twist, or carefully work a flathead screwdriver between the hose and fitting to break the bond. Allow any remaining coolant to drain into the pan.
6. 6

   Inspect and clean connection points
   Inspect the radiator outlet and water pump inlet for corrosion, damage, or debris. Use a wire brush to clean both connection surfaces, removing any old rubber residue, corrosion, or scale buildup. Wipe clean with a shop towel. Inspect fittings for cracks or damage that could cause leaks.
7. 7

   Install new hose clamps on new hose
   Slide one new worm-gear hose clamp onto each end of the new lower radiator hose. Position the clamps approximately 4 inches from each hose end with the screw mechanism accessible from the top or outside for easier tightening after installation.
8. 8

   Install new lower radiator hose
   Push one end of the new hose firmly onto the water pump inlet until it bottoms against the fitting ridge (approximately 2 inches of engagement). Then route the hose to the radiator and push the opposite end firmly onto the radiator outlet until it also bottoms against the fitting ridge. Ensure the hose routing does not contact any sharp edges, the fan, or moving components.
9. 9

   Secure hose clamps
   Slide the hose clamp at the water pump connection forward so it is positioned 1 inch from the end of the hose, centered over the fitting. Tighten the clamp screw firmly with a flathead screwdriver until the hose is secure but not crushed. Repeat for the radiator connection clamp. Ensure clamp screws are positioned for future access.
10. 10

    Close radiator drain and refill cooling system
    Close the radiator petcock drain valve by turning clockwise until snug (hand-tight only). Using a funnel, slowly pour coolant into the radiator filler neck. Fill until coolant level reaches the bottom of the filler neck. Pause periodically to allow air bubbles to escape. Gently squeeze the upper radiator hose several times to help purge air from the system.
11. 11

    Burp cooling system
    With the radiator cap still off, start the engine and allow it to idle. Watch the coolant level in the radiator and add coolant as needed as air is purged from the system. The coolant level will drop as the thermostat opens and coolant circulates. Continue adding coolant until the level stabilizes at the bottom of the filler neck. Monitor for approximately 5 minutes or until the thermostat opens and upper radiator hose becomes hot.
12. 12

    Install radiator cap and check for leaks
    With the engine still running, carefully install the radiator cap. Visually inspect both lower radiator hose connections for any signs of coolant leakage. Check underneath the vehicle for drips. Allow the engine to reach normal operating temperature while monitoring for leaks. Shut off the engine.

Reassembly

1. Reinstall radiator cap securely after final coolant level check
2. Wipe down all components and clean up any coolant spills with water
3. Dispose of old coolant and hose according to local environmental regulations

Verification

• Start the engine and allow it to reach normal operating temperature while monitoring the temperature gauge for proper operation
• Visually inspect both hose clamp connections for any signs of coolant seepage or leakage
• Check coolant level in radiator after engine cools (should be at bottom of filler neck)
• Test drive the vehicle and recheck coolant level and inspect for leaks after the system has fully heat cycled
• Verify no coolant odor in the engine compartment or visible drips under the vehicle after 24 hours of operation

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