Radiator Hoses - Both

Remove and replace both upper and lower radiator coolant hoses on the 2008 Dodge Viper 8.4L V10, including coolant drain and refill.

Warnings

Tools required

Parts

• Upper radiator hose × 1 — Mopar 5179331AA or equivalent
• Lower radiator hose × 1 — Mopar 5179332AA or equivalent
• Hose clamps (if reusing originals are damaged) × 4 — Use OEM specification worm-drive clamps

Fluids

• Mopar HOAT coolant 50/50 — 19 qt

Preparation

1. Verify engine is completely cold to the touch
2. Park vehicle on level surface and engage parking brake
3. Place drain pan under radiator drain cock (passenger side lower corner of radiator)
4. Remove radiator cap slowly to release any residual pressure

Procedure

1. 1

   Drain cooling system
   Open the radiator drain cock (petcock) located at the passenger side lower corner of the radiator by turning counterclockwise. Allow coolant to drain completely into the drain pan. If the drain cock is stuck or damaged, proceed to disconnect the lower hose instead to drain the system. Collect and measure the old coolant to assess system capacity.
2. 2

   Remove engine cover (if equipped)
   If your Viper is equipped with an engine cover, lift it straight up to disengage the mounting grommets and set aside. This provides better access to the upper radiator hose connection at the thermostat housing.
3. 3

   Remove upper radiator hose at radiator end
   Locate the upper radiator hose connection at the top driver side of the radiator. Using hose clamp pliers or a flathead screwdriver, loosen the worm-drive clamp and slide it back onto the hose at least 2 inches from the radiator neck. Twist the hose gently to break the seal, then pull it straight off the radiator inlet. Be prepared for residual coolant spillage.
4. 4

   Remove upper radiator hose at engine end
   Follow the upper radiator hose to the engine-side connection at the coolant outlet/thermostat housing at the front of the engine. Verify the exact connection point against the factory service manual for the 8.4L V10. Loosen the worm-drive clamp and slide it back onto the hose. Twist and pull the hose off the thermostat housing neck. Remove the entire upper hose assembly from the vehicle.
5. 5

   Remove lower radiator hose at radiator end
   Working from underneath or through the front of the vehicle, locate the lower radiator hose connection at the bottom driver side of the radiator. Loosen the worm-drive clamp and slide it back. Twist the hose to break the seal and pull it off the radiator outlet. Additional coolant will drain at this point.
6. 6

   Remove lower radiator hose at engine end
   Trace the lower radiator hose to its connection at the water pump inlet (located low on the front of the engine). Loosen the worm-drive clamp and slide it back. Twist and remove the hose from the water pump. Remove the entire lower hose assembly from the vehicle. Inspect both hose routing paths for any debris or obstructions.
7. 7

   Inspect and clean connection points
   Inspect all four hose connection necks (radiator inlet/outlet, thermostat housing, water pump) for corrosion, pitting, or damage. Use a wire brush or abrasive pad to clean any rust, scale, or old coolant residue from the necks. Verify that all necks are smooth and free of sharp edges that could cut the new hoses. Inspect the hose clamps for corrosion or damage; replace if threads are stripped or band is weakened.
8. 8

   Install new lower radiator hose
   Slide new worm-drive clamps onto the lower radiator hose before installation (one for each end). Position the lower hose and push it firmly onto the water pump inlet until it seats completely against the bead or stop. Slide the clamp into position approximately 1/4 inch from the end of the hose and tighten securely. Route the hose to the radiator outlet, ensuring it does not contact exhaust components or sharp edges, then install and tighten the radiator-end clamp in the same manner.
9. 9

   Install new upper radiator hose
   Slide new worm-drive clamps onto the upper radiator hose before installation. Push the engine-end of the hose firmly onto the thermostat housing neck until fully seated. Position the clamp approximately 1/4 inch from the hose end and tighten securely. Route the hose to the radiator inlet, verifying clearance from moving parts and hot surfaces, then install and secure the radiator-end connection with its clamp.
10. 10

    Close drain cock and prepare for refill
    Close the radiator drain cock (petcock) by turning it clockwise until snug. Do not overtighten as the plastic threads can strip. Verify all hose clamps are tight and all connections are secure. Wipe down the area with shop towels to make leak detection easier during the next steps.
11. 11

    Fill cooling system
    Using a funnel, slowly pour Mopar HOAT 50/50 coolant mixture into the radiator filler neck. Fill until coolant reaches the bottom of the filler neck. Pause periodically to allow air bubbles to escape. Locate and open the cooling system bleed valve if equipped; verify its exact location against the factory service manual for the 2008 Viper 8.4L V10 before attempting to purge trapped air. Close the bleed valve when steady coolant flows from it without air bubbles.
    ℹ️The Viper cooling system has a high-mounted thermostat and is prone to air pockets. Proper bleeding is critical to prevent overheating.
12. 12

    Initial run and burp procedure
    With the radiator cap still off, start the engine and allow it to idle. Monitor the coolant level and add additional coolant as the level drops due to air purging. Run the engine until the cooling fans cycle on, indicating the thermostat has opened. Watch for circulation in the radiator and verify both radiator hoses become hot (upper hose should be hotter than lower). Add coolant as needed to maintain level at the bottom of the filler neck.
    ⚠Monitor engine temperature gauge closely during this process. If temperature approaches the red zone before fans cycle, shut off the engine and allow cooling before investigating blockage or air pocket issues.
13. 13

    Final fill and cap installation
    After the cooling fans cycle and the engine returns to normal operating temperature (thermostat closed again), shut off the engine. Allow a brief cooling period, then top off the radiator to the bottom of the filler neck. Install the radiator cap, ensuring it seats properly and locks into position. Check the coolant overflow reservoir and fill to the FULL COLD mark with the same HOAT coolant.
14. 14

    Inspect for leaks
    With the engine off, carefully inspect all four hose connections for signs of coolant seepage. Check the radiator drain cock for leaks. Wipe all connections dry with a shop towel and look for fresh coolant accumulation. Inspect the ground under the vehicle for drips. If any leaks are found, allow the system to cool, tighten the affected clamp, and retest.

Reassembly

1. Reinstall engine cover by aligning mounting grommets and pressing down firmly until seated
2. Clean any coolant spills from engine bay and chassis components with water and shop towels
3. Dispose of old coolant according to local environmental regulations

Verification

• Start the engine and allow it to reach full operating temperature while monitoring the temperature gauge for normal operation
• Verify both cooling fans cycle on and off properly
• Check that both radiator hoses are hot to the touch (use caution) with upper hose hotter than lower, indicating proper circulation
• After the engine cools completely, recheck coolant level at radiator neck and overflow reservoir; top off if needed
• Perform a final visual inspection of all hose connections for leaks after the first drive cycle
• After 50-100 miles of driving, recheck coolant level and inspect connections again for any delayed seepage

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