Radiator Hose - Lower

Replace the lower radiator hose on a 2005 Dodge Viper 8.3L V10, including coolant drain, hose removal, and refill procedures.

Warnings

Tools required

Parts

• Lower radiator hose × 1 — Use OEM specification
• Hose clamps (if reusing originals shows wear) × 2 — Worm-drive style, appropriate diameter

Fluids

• Zerex G-05 HOAT 50/50 — 4 qt

Preparation

1. Ensure engine is completely cold to the touch (minimum 2 hours after last operation).
2. Position vehicle on level ground and engage parking brake.
3. Place drain pan beneath radiator drain valve location on passenger side lower radiator tank.
4. Have approximately 4 quarts of Zerex G-05 HOAT 50/50 coolant available for refill.

Procedure

1. 1

   Drain cooling system
   Locate the radiator drain valve (petcock) on the lower passenger side of the radiator. Open the drain valve by rotating counterclockwise and allow coolant to drain into the pan. The lower hose location means full drainage is not required, but draining 1-2 gallons will minimize spillage. Leave drain valve open during hose removal.
2. 2

   Access lower radiator hose connections
   The lower radiator hose connects the bottom radiator outlet to the water pump inlet on the front of the engine block. Identify both connection points. On the 2005 Viper, the lower hose routing passes along the front driver side of the engine with minimal obstruction.
3. 3

   Loosen radiator-end hose clamp
   Locate the hose clamp securing the lower hose to the radiator outlet nipple. Using a flat-blade screwdriver or hose clamp pliers, loosen the worm-drive clamp by rotating the screw counterclockwise. Slide the clamp back along the hose away from the radiator connection, at least 2 inches to clear the nipple barbs.
4. 4

   Loosen water pump-end hose clamp
   Locate the hose clamp at the water pump inlet connection on the front of the engine block. Loosen the worm-drive clamp and slide it back along the hose away from the water pump connection, ensuring it clears the nipple completely.
5. 5

   Remove lower radiator hose from radiator
   Twist the hose back and forth while pulling to break the seal between the hose and radiator outlet nipple. Remove the hose from the radiator first. Residual coolant will drain from the hose and radiator; keep the drain pan positioned to catch spillage. If the hose is stuck, carefully use a flat-blade screwdriver to pry between the hose end and radiator flange, working around the circumference.
6. 6

   Remove lower radiator hose from water pump
   Twist and pull the hose from the water pump inlet connection. Additional coolant will drain from the water pump and engine block passages. Remove the hose completely from the engine bay. Inspect both the radiator outlet and water pump inlet nipples for corrosion, cracks, or damage.
7. 7

   Prepare new lower radiator hose
   If reusing original clamps, inspect for corrosion, stripped threads, or weakened spring tension. Replace clamps if any deterioration is visible. Slide both hose clamps onto the new hose before installation, positioning one clamp near each end. Ensure clamp screw heads are accessible once hose is routed (typically facing upward or outward).
8. 8

   Install hose onto water pump inlet
   Route the new hose into position following the original path along the front driver side of the engine. Push the engine-end of the hose firmly onto the water pump inlet nipple until it seats completely against the flange. The hose should cover all barbs or ridges on the nipple. Twist slightly while pushing to ease installation.
9. 9

   Install hose onto radiator outlet
   Push the radiator-end of the hose firmly onto the lower radiator outlet nipple until fully seated against the radiator tank flange. Ensure the hose routing does not create sharp bends or contact with moving components (fan, belt, etc.). The hose should lay naturally without tension.
10. 10

    Secure hose clamps
    Position the radiator-end clamp 1/4 to 1/2 inch back from the end of the hose, centered over the nipple. Tighten the clamp until snug and the hose is compressed evenly, approximately 4.5 Nm (40 in-lb). Do not overtighten. Repeat for the water pump-end clamp. Do not overtighten, as excessive clamping force can cut into the hose and cause premature failure.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
11. 11

    Close radiator drain and refill system
    Close the radiator drain valve by rotating clockwise until finger-tight. Remove the coolant pressure cap from the radiator filler neck. Using a funnel, slowly add Zerex G-05 HOAT 50/50 coolant to the radiator until the level reaches the filler neck. Add coolant gradually to allow air to escape. Approximately 4 to 6 quarts will be needed to replace drained coolant and hose volume; add until the system is full and refuses more.
12. 12

    Bleed air from cooling system
    With the radiator cap still off, start the engine and allow it to idle. Monitor coolant level in the radiator; add coolant as the level drops while air purges from the system. Run the engine until the thermostat opens (indicated by the upper radiator hose becoming hot as coolant begins to circulate). Maintain coolant level at the filler neck throughout this process. Once thermostat opens and no additional air bubbles emerge, turn off the engine.
13. 13

    Final coolant level adjustment
    Allow engine to cool for 10 minutes. Check coolant level in the radiator and top off to the filler neck if needed. Install the radiator pressure cap securely. Check the coolant overflow reservoir level; it should be between the MIN and MAX marks on the cold side. Add coolant to the reservoir if needed to reach the cold FULL mark.

Reassembly

1. Torque all hose clamps to specification to prevent leaks without damaging the hose.
2. Ensure proper coolant system bleed to avoid air pockets that can cause overheating.
3. Verify hose routing does not contact moving components or create tight bends.

Verification

• Start the engine and allow it to reach operating temperature while monitoring for leaks at both hose connections.
• Check coolant temperature gauge remains in normal range (approximately midpoint) during idle and light throttle.
• After engine cools, verify coolant level in radiator remains at filler neck and reservoir is at cold FULL mark.
• Inspect under vehicle for coolant drips or puddles after the first drive cycle.
• Recheck hose clamp tightness after the first heat cycle (engine cool, then retorque clamps to specification).

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