Radiator Hose - Upper

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

Warnings

Tools required

Parts

• Upper radiator hose × 1 — Use OEM specification
• Hose clamps (if reusing originals are damaged) × 2 — Worm-drive or OEM spring clamps

Fluids

• Zerex G-05 HOAT 50/50 — 2 qt

Preparation

1. Ensure engine is completely cold (minimum 2 hours after last operation)
2. Park vehicle on level surface and apply parking brake
3. Place drain pan beneath radiator drain valve location
4. Open hood and verify access to upper radiator hose at radiator and thermostat housing connections

Procedure

1. 1

   Relieve cooling system pressure
   Slowly rotate the pressure cap on the coolant expansion (degas) bottle counterclockwise to the first detent (safety position) and allow any residual pressure to escape. Once pressure is fully released, press down and continue rotating counterclockwise to remove the cap completely. Set cap aside on clean shop towel.
2. 2

   Drain coolant from system
   Open the radiator petcock drain valve at the bottom of the radiator (passenger side) by rotating counterclockwise. Allow approximately 2-3 quarts of coolant to drain into the drain pan. This reduces coolant loss and mess during hose removal. Close the petcock when draining slows to a trickle.
3. 3

   Disconnect upper hose at radiator
   Locate the upper radiator hose connection at the top of the radiator (driver side). If equipped with worm-drive clamps, use a flat-blade screwdriver to loosen the clamp screw and slide the clamp 2-3 inches back onto the hose, away from the radiator neck. If equipped with OEM spring clamps, use hose clamp pliers to compress the clamp ears and slide it back along the hose. Twist the hose gently while pulling to break the seal, then pull the hose off the radiator neck. Allow any remaining coolant to drain into the pan.
4. 4

   Disconnect upper hose at thermostat housing
   Follow the upper hose to the thermostat housing connection on the engine (front of engine, center). Loosen or compress the hose clamp at this connection using the same method as the radiator end, and slide the clamp back onto the hose. Twist and pull the hose to remove it from the thermostat housing outlet. Expect additional coolant drainage.
5. 5

   Remove upper radiator hose
   Maneuver the upper radiator hose out of the engine bay, taking note of its routing path and any clearance points. Inspect the hose routing for reference during installation. If reusing clamps, slide them completely off the old hose.
6. 6

   Prepare surfaces and new hose
   Clean the radiator neck and thermostat housing outlet with shop towels, removing any old coolant residue, corrosion, or rubber debris. Inspect both connection points for cracks or damage. If reusing original clamps, inspect them for corrosion, stripped threads (worm-drive type), or weakened springs (spring type). Replace if damaged. Slide the appropriate clamps onto the new upper radiator hose before installation.
7. 7

   Install new upper hose at thermostat housing
   Position the new upper radiator hose onto the thermostat housing outlet first, ensuring the hose is fully seated over the outlet (typically 1.5-2 inches of overlap). Slide the hose clamp into position over the connection point, approximately 0.5 inch from the end of the outlet neck. Tighten worm-drive clamps to 3.0 Nm (2.0 lb-ft), or position spring clamp fully in its groove if using OEM style.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
8. 8

   Install new upper hose at radiator
   Route the hose to the radiator following the same path as the original, ensuring it does not contact sharp edges, exhaust components, or moving parts. Push the hose fully onto the radiator neck until seated. Slide the clamp into position over the connection point, approximately 0.5 inch from the end of the radiator neck. Tighten worm-drive clamp to 3.0 Nm (2.0 lb-ft), or position spring clamp fully in its groove.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
9. 9

   Refill cooling system
   Close the radiator petcock if not already closed. Using a funnel at the coolant expansion (degas) bottle, slowly pour the OEM-specified HOAT 50/50 coolant into the system. Fill until coolant reaches the base of the filler neck. Pause periodically to allow air pockets to burp out. Gently squeeze the upper and lower radiator hoses several times to help release trapped air.
10. 10

    Burp cooling system and verify level
    Install the expansion bottle cap loosely (do not fully tighten). Start the engine and allow it to idle with the heater set to maximum temperature. Monitor coolant level at the expansion bottle as the thermostat opens and coolant circulates. Add coolant as needed to maintain proper level. Once the thermostat opens and coolant circulates (upper hose becomes hot), rev engine to 2000-2500 RPM briefly 2-3 times to help purge air. Shut off engine, allow to cool for 5 minutes, then top off coolant to proper level and install radiator cap fully.

Reassembly

1. Verify both hose clamps are positioned correctly and tightened to specification
2. Confirm upper radiator hose routing does not interfere with any moving parts, fan blades, or exhaust components
3. Double-check radiator petcock is closed before final test drive

Verification

• With engine cold, verify coolant level is at full mark in radiator filler neck
• Start engine and visually inspect both hose connections for leaks while engine warms up
• Once engine reaches operating temperature, verify upper radiator hose is firm and hot, indicating proper coolant circulation
• After first test drive (10-15 minutes), recheck coolant level when engine is cold and top off if necessary
• Monitor coolant level and inspect connections after 50-100 miles of driving to ensure no slow leaks have developed

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