Engine Oil Cooler

Removal and replacement of the engine oil cooler assembly on the 2008 Dodge Viper 8.4L V10, including coolant draining, hose disconnection, and mounting hardware removal.

Warnings

Tools required

Parts

• Engine oil cooler assembly × 1 — Use OEM specification
• Oil cooler mounting gasket/O-rings × 1 — Use OEM specification
• Coolant hose clamps (if damaged) × 2 — Use OEM specification
• Engine coolant × 1 — Mopar HOAT 50/50
• Engine oil × 1 — 0W-40 full synthetic

Fluids

• coolant — 19 qt
• engine_oil — 11 qt

Preparation

1. Park vehicle on level surface and allow engine to cool completely (minimum 2 hours after operation).
2. Disconnect negative battery cable.
3. Remove engine cover by releasing mounting grommets.
4. Place drain pan under front of vehicle to capture coolant and oil.
5. Remove radiator cap slowly to relieve any residual system pressure.

Procedure

1. 1

   Drain engine coolant
   Position large drain pan beneath radiator. Open radiator petcock or remove lower radiator hose at radiator to drain coolant. Capture coolant for proper disposal or reuse if clean. Allow system to drain completely.
2. 2

   Access oil cooler assembly
   The oil cooler is an oil-to-coolant heat exchanger mounted to the engine; verify its exact location using the factory service manual for the 2008 Viper 8.4L V10 before proceeding. Identify the oil cooler assembly with coolant lines and oil feed/return lines attached, and clean the surrounding area to prevent contamination during disassembly. From underneath the vehicle, identify the oil cooler assembly with coolant lines and oil feed/return lines attached. Clean the surrounding area to prevent contamination during disassembly.
3. 3

   Disconnect coolant lines
   Using hose clamp pliers, reposition or remove the coolant hose clamps securing the inlet and outlet coolant hoses to the oil cooler. Mark hose orientation with tape or marker. Twist hoses gently to break seal, then pull off cooler fittings. Be prepared for residual coolant spillage. Plug hose ends with clean rags to prevent contamination.
4. 4

   Disconnect oil feed and return lines
   Locate the oil feed line (from engine block) and return line (to oil pan) connections at the oil cooler. Using appropriate wrenches, loosen the threaded fittings securing the oil lines to the cooler. Expect engine oil to drain from these connections. Have drain pan positioned to catch oil. Cap or plug line ends immediately after disconnection to prevent dirt ingress.
5. 5

   Remove oil cooler mounting hardware
   Locate and remove the mounting bolts securing the oil cooler bracket to the engine block. Refer to the factory service manual for the exact number and size of bolts holding the cooler assembly on the 2008 Viper 8.4L V10. Support the cooler with one hand while removing the final fastener to prevent it from falling.
6. 6

   Remove oil cooler assembly
   Carefully maneuver the oil cooler assembly away from the engine block. It may require angling to clear surrounding components. Inspect the mounting surface on the engine block for damage or debris. Remove old gasket material or O-rings from both the cooler and block mounting surfaces using a plastic scraper. Do not gouge aluminum surfaces.
7. 7

   Inspect and prepare new oil cooler
   Compare new oil cooler to old unit to verify correct replacement part. Check that all mounting holes and port locations match. Inspect new gaskets or O-rings included with replacement cooler. Clean mounting surfaces on block thoroughly with clean shop towels and brake cleaner. Ensure no debris or old gasket material remains.
8. 8

   Install new gaskets and position oil cooler
   Install new gasket or O-rings onto the oil cooler assembly per manufacturer instructions. Some designs use O-rings in grooves on the cooler body, others use flat gaskets. Light application of clean engine oil on O-rings aids installation. Position new oil cooler onto engine block mounting location, aligning mounting holes and port locations.
9. 9

   Install oil cooler mounting hardware
   Thread mounting bolts by hand to ensure proper thread engagement and avoid cross-threading. Tighten bolts in a crossing pattern to ensure even gasket compression. Tighten bolts to the factory service manual torque specification for the 2008 Viper 8.4L V10 oil cooler mounting bolts (specification not available in database).
10. 10

    Reconnect oil feed and return lines
    Remove plugs from oil line ends. Thread oil feed and return line fittings into new oil cooler by hand first to verify proper thread engagement. Tighten fittings with appropriate wrenches to proper specification. Do not overtighten as this can damage fittings or crack the cooler housing.
11. 11

    Reconnect coolant lines
    Remove rags from coolant hose ends. Verify hoses are oriented correctly per marks made during removal. Push coolant hoses firmly onto cooler inlet and outlet fittings until fully seated. Install new hose clamps or reposition original clamps beyond the bead on the fittings. Ensure clamps are tight and properly positioned.
12. 12

    Refill engine coolant
    Close radiator petcock or reinstall lower radiator hose if removed. Fill cooling system with Mopar HOAT 50/50 coolant at the designated fill/pressure reservoir per the factory service manual for the 2008 Viper. Follow the specified fill and air-bleed procedure. Fill until coolant reaches proper level, allow time for air to burp from system, and top off as needed. Fill until coolant reaches proper level. Allow time for air to burp from system. Top off as needed. Install radiator cap.
13. 13

    Refill engine oil and bleed cooling system
    Check engine oil level and top off with the factory-specified full synthetic oil (verify viscosity, commonly 5W-40, per owner's manual/FSM) as needed to compensate for oil lost during cooler removal. Start engine and allow to idle while monitoring for leaks at oil cooler connections. Watch temperature gauge. Run engine until thermostat opens and cooling fan cycles. Check for coolant leaks at hose connections. Shut off engine and recheck coolant level when cool, topping off as necessary.

Reassembly

1. Reinstall engine cover by pressing onto mounting grommets.
2. Reconnect negative battery cable.
3. Double-check all coolant hose clamps and oil line fittings for proper tightness.
4. Clean any spilled fluids from engine bay and undercarriage.

Verification

• Start engine and verify no coolant or oil leaks from oil cooler connections after engine reaches operating temperature.
• Verify cooling system maintains proper temperature and cooling fan operates normally.
• Check engine oil level after test drive and top off if necessary.
• Recheck coolant level after engine cools completely and top off to proper level.
• Monitor oil pressure gauge during test drive to confirm normal oil pressure readings.
• Inspect under vehicle for any signs of coolant or oil drips after 24-48 hours of operation.

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