cooling

Water Pump

for 1966 Chevrolet Corvette 327ci V8 · RWD

Difficulty

Moderate

Time

2.5 h

Tools

Steps

✓Expert-verified. This procedure has been reviewed by a person. Always follow the vehicle's factory service information and torque specs.

Complete removal and replacement of the water pump on a 1966 Chevrolet Corvette 327ci V8, including coolant drain, accessory removal, and refill procedures.

Warnings

⚠️Allow engine to cool completely before starting work. Hot coolant under pressure can cause severe burns.

⚠DEX-COOL (orange) coolant was not used in 1966. Original coolant was green ethylene glycol. If system has been converted to DEX-COOL, continue using it. If original green coolant, use traditional green coolant instead.

⚠1966 Corvettes may have either a standard or air conditioning equipped water pump. Verify pump type before ordering parts.

ℹ️Disconnect battery ground cable before beginning work to prevent accidental fan engagement or electrical shorts.

Tools required

Socket set (3/8" and 1/2" drive)Essential

Torque wrench (10-30 lb-ft range)Essential

Drain pan (3+ gallon capacity)Essential

Box-end wrench setEssential

Screwdriver set (flat and Phillips)Essential

Gasket scraper or plastic scraperEssential

Belt tension gauge (optional for power steering/AC)

Cooling system pressure tester

Wire brush

Shop ragsEssential

Parts

Water pump assembly × 1 — Use OEM specification
Water pump gasket × 1 — Use OEM specification
Lower radiator hose (if deteriorated) × 1 — Use OEM specification
Heater hose (if deteriorated) × 1 — Use OEM specification
Fan belt(s) × 1 — Use OEM specification

Fluids

DEX-COOL Extended Life (Orange) — 10 qt

Preparation

Position vehicle on level ground and allow engine to cool completely (minimum 2 hours after operation).
Disconnect negative battery cable.
Place drain pan beneath radiator drain petcock.
Remove radiator cap slowly to release any residual pressure.
Verify replacement water pump matches original configuration (standard vs. A/C equipped).

Procedure

1
Drain cooling system
Open radiator drain petcock at bottom of radiator and drain coolant into pan. If engine block has drain plugs (located on both sides of block near freeze plugs), remove them to fully drain system. Collect and properly dispose of old coolant according to local regulations.
2
Remove fan shroud (if equipped)
Remove the 4 fan shroud mounting bolts and carefully lift shroud upward enough to clear fan blades, then rest it on radiator core support. Do not remove shroud completely unless necessary.
3
Remove fan and fan clutch assembly
Remove the 4 fan-to-fan clutch bolts (or fan-to-pulley bolts if no clutch). Lift fan assembly straight up and out. All fan and fan clutch bolts on this application are standard right-hand thread - turn counterclockwise to loosen. Store fan in safe location where blades will not be damaged.
4
Remove drive belts
Loosen alternator adjustment bolt and pivot bolt, push alternator toward engine, and remove alternator belt. If power steering equipped, loosen power steering pump mounting and adjustment bolts and remove power steering belt. If A/C equipped, loosen A/C compressor and remove compressor belt. Mark or photograph belt routing for reinstallation.
5
Disconnect hoses from water pump
Using pliers or screwdriver, loosen hose clamps on lower radiator hose at water pump inlet and bypass hose(s) at water pump. Twist hoses to break seal and carefully pull off pump nipples. If hoses are stuck, carefully cut them off rather than risk damaging new pump. Inspect hoses for cracks, swelling, or deterioration and replace if necessary.
Torque spec
Hose Clamps3 Nm (2 lb-ft)
6
Remove water pump pulley
Remove the 4 water pump pulley bolts. It may be necessary to hold the pulley with a strap wrench or have an assistant hold it while loosening bolts. Remove pulley from water pump hub.
7
Remove water pump mounting bolts
Remove the 4 water pump mounting bolts securing pump to engine block front. Note bolt length and position as they may vary. Carefully pull water pump away from engine block. It may be stuck due to old gasket material - gently pry at the pump flange (not the sealing surface) if necessary.
Torque spec
Water Pump Bolts25 Nm (18 lb-ft)
8
Clean mounting surfaces
Using gasket scraper and wire brush, thoroughly clean all old gasket material from timing chain cover water pump mating surface. Ensure surface is completely clean and free of debris, oil, or coolant. Clean bolt holes with brake cleaner and compressed air if available. Do not gouge or scratch sealing surfaces.
9
Install new water pump gasket
Position new water pump gasket on timing chain cover. A thin film of water-resistant gasket sealer on both sides of gasket is recommended to prevent leaks. Align all bolt holes and ensure gasket is fully seated in position.
10
Install new water pump
Carefully align new water pump with gasket and timing chain cover. Start all 4 mounting bolts by hand to ensure proper thread engagement and alignment. Once all bolts are started, tighten in a criss-cross pattern to specification using torque wrench. Do not overtighten as this can distort pump housing or crack casting.
Torque spec
Water Pump Bolts25 Nm (18 lb-ft)
11
Install water pump pulley
Position water pump pulley on pump hub and install the 4 pulley bolts. Snug bolts but do not fully tighten yet - final tightening will be done after belts are installed to prevent hub rotation.
12
Reconnect coolant hoses
Slide new hose clamps onto hoses. Install lower radiator hose and bypass hose(s) onto water pump nipples, ensuring hoses are fully seated. Position clamps 1/4 inch from hose ends and tighten to specification using screwdriver or nut driver.
Torque spec
Hose Clamps3 Nm (2 lb-ft)
13
Install drive belts and tension
Route belts according to previously noted or photographed configuration. Install alternator belt first, then power steering (if equipped), then A/C belt (if equipped). Tension each belt by adjusting component position - proper tension allows 1/2 inch deflection at longest belt span with moderate thumb pressure. Tighten all adjustment and mounting bolts securely.
14
Final tighten pulley and install fan
With belts providing resistance, final tighten the 4 water pump pulley bolts securely. Install fan assembly and secure with the 4 fan mounting bolts. Torque to specification per fan type (typically 15-20 lb-ft, but verify). Reinstall fan shroud (if equipped) with 4 mounting bolts.
15
Refill cooling system and bleed air
Close all drain plugs. Fill radiator with coolant mixture (50/50 conventional green ethylene glycol coolant and distilled water) until radiator is full. Start engine with radiator cap off and allow to warm up to operating temperature. As thermostat opens and coolant circulates, air pockets will escape and coolant level will drop - add coolant as necessary. Squeeze upper radiator hose several times to help purge air. When coolant level stabilizes and no more bubbles emerge, install radiator cap. Check for leaks around water pump and all hose connections.
⚠Engine will be hot during bleeding process. Keep hands clear of fan blades and hot components.

Reassembly

Verify all belts are properly tensioned and tracking correctly on pulleys.
Reconnect negative battery cable.
Top off coolant recovery tank to cold fill line if equipped.

Verification

Start engine and allow to reach normal operating temperature while monitoring temperature gauge.
Check for coolant leaks at water pump gasket, hose connections, and drain plugs.
Verify cooling fan operates correctly (mechanical clutch engagement or electric fan operation).
Check belt tension after 50-100 miles of operation and adjust if necessary.
Verify heater produces hot air when heater controls are set to heat.
Monitor coolant level over next few days and top off as necessary after air pockets purge from system.