Radiator Hose - Upper

Replace the upper radiator hose on a 2008 Dodge Viper 8.4L V10, including coolant drain and refill.

Warnings

Tools required

Parts

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

Fluids

• Mopar HOAT coolant 50/50 — 3 qt

Preparation

1. Ensure the engine is completely cold to the touch
2. Park the vehicle on level ground
3. Open the hood and secure it in the open position
4. Locate the radiator cap on the radiator and the upper radiator hose connection points (radiator outlet and thermostat housing on engine)
5. Place a large drain pan under the radiator drain petcock on the driver's side lower corner of the radiator

Procedure

1. 1

   Relieve cooling system pressure
   Slowly rotate the cooling system pressure cap (located on the coolant pressure/overflow bottle) counterclockwise to the first detent and allow any residual pressure to escape. Once pressure is fully relieved, press down and continue rotating counterclockwise to remove the cap completely. Set the cap aside in a clean location.
2. 2

   Drain coolant from radiator
   Open the radiator drain petcock (verify its location on the radiator per factory documentation) by turning it counterclockwise. If no accessible petcock is present, drain via the lower radiator hose instead. Allow coolant to drain into the drain pan until the level drops below the upper radiator hose connection point on the radiator. You do not need to drain the entire system. Once sufficient coolant has drained, close the petcock by turning it clockwise until snug.
3. 3

   Loosen radiator-side hose clamp
   Locate the hose clamp securing the upper radiator hose to the radiator outlet neck. If equipped with a worm-drive clamp, use a flathead screwdriver to loosen the clamp by turning the screw counterclockwise. If equipped with a spring clamp, use hose clamp pliers to compress the clamp ears and slide it back along the hose away from the radiator neck at least 2 inches. Do not remove the clamp from the hose yet.
4. 4

   Disconnect hose from radiator
   Twist the upper radiator hose back and forth while pulling away from the radiator outlet neck to break the seal. Once free, pull the hose completely off the radiator neck. Expect residual coolant to spill from both the hose and radiator neck; have shop towels ready. Slide the loosened clamp off the old hose end.
5. 5

   Loosen engine-side hose clamp
   Locate the hose clamp securing the upper radiator hose to the engine coolant outlet/thermostat housing. Trace the hose from the radiator to confirm the exact connection point before proceeding. Loosen this clamp using the same method as step 3, sliding it back along the hose at least 2 inches away from the thermostat housing connection.
6. 6

   Remove upper radiator hose
   Twist the hose back and forth while pulling away from the thermostat housing outlet to break the seal. Remove the hose completely from the vehicle. Slide both clamps off the old hose. Inspect the clamps for damage, rust, or stripped threads; replace if necessary.
7. 7

   Clean connection surfaces
   Use a shop towel to clean the radiator outlet neck and thermostat housing outlet. Remove any old rubber residue, corrosion, or debris from both connection points. Inspect both surfaces for cracks or damage that could cause leaks.
8. 8

   Install hose clamps on new hose
   Slide both hose clamps onto the new upper radiator hose before installation. Position one clamp approximately 3 inches from each end of the hose with the clamp screw or spring mechanism facing outward for easy access once installed.
9. 9

   Connect new hose to thermostat housing
   Push the engine-side end of the new upper radiator hose firmly onto the thermostat housing outlet until it bottoms out against the housing stop. Ensure the hose is fully seated. Slide the hose clamp forward to a position 1/2 to 3/4 inch from the end of the hose, centered over the outlet neck. Tighten the clamp securely with a flathead screwdriver (worm-drive) or position and release the spring clamp with pliers.
10. 10

    Connect new hose to radiator
    Push the radiator-side end of the new upper radiator hose firmly onto the radiator outlet neck until it bottoms out. Slide the hose clamp forward to a position 1/2 to 3/4 inch from the end of the hose, centered over the outlet neck. Tighten the clamp securely.
11. 11

    Refill cooling system
    Using a funnel, pour Mopar HOAT 50/50 premixed coolant into the coolant reservoir/pressure bottle until the level reaches the specified fill mark, following the factory bleed procedure to purge trapped air. Add approximately 3 quarts to compensate for coolant lost during hose replacement. Install the cooling system pressure cap on the coolant reservoir/pressure bottle by pushing down and rotating clockwise until it locks into place.
12. 12

    Burp cooling system and check for leaks
    Start the engine and allow it to reach normal operating temperature with the heater set to maximum temperature and fan on high. Monitor the upper radiator hose connections closely for any signs of coolant leakage. As the thermostat opens and coolant circulates, the upper radiator hose should become hot to the touch. Allow the engine to run for 10 minutes, then shut it off. Once cooled, recheck the coolant level in the radiator and top off if necessary. Check for leaks again at both hose connections.

Reassembly

1. Reassembly is completed during the installation steps above
2. Ensure both hose clamps are positioned correctly and tightened securely
3. Double-check that the radiator drain petcock is closed completely

Verification

• Visually inspect both hose connections for coolant leaks with the engine at operating temperature
• Verify the upper radiator hose becomes hot after the thermostat opens, confirming coolant circulation
• Check coolant level in the radiator after the engine has cooled and top off if necessary
• Inspect the ground under the vehicle for any coolant drips after a test drive
• Confirm heater output is hot, indicating proper coolant flow through the system

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