Radiator

Complete removal and replacement of the radiator assembly on a 1970 AMC Rebel Machine with 390ci V8 engine, including coolant drain, hose disconnection, and transmission cooler line service.

Warnings

Tools required

Parts

• Radiator assembly × 1 — Use OEM specification or quality aftermarket equivalent
• Upper radiator hose × 1 — Replace if cracked or deteriorated
• Lower radiator hose × 1 — Replace if cracked or deteriorated
• Hose clamps (assorted) × 4 — Use worm-gear style clamps
• Radiator petcock or drain plug × 1 — Replace if damaged
• Transmission cooler line o-rings × 2 — Use OEM specification

Fluids

• Ethylene glycol antifreeze/coolant (50/50 mix) — 16 qt

Preparation

1. Ensure engine is completely cold to the touch
2. Position vehicle on level ground and apply parking brake
3. Disconnect negative battery cable to prevent accidental fan engagement
4. Place large drain pan beneath radiator drain petcock location
5. Remove radiator cap slowly to relieve any residual pressure

Procedure

1. 1

   Drain cooling system
   Open the radiator petcock at the bottom of the radiator on the driver's side, or remove the lower radiator hose at the radiator to drain coolant completely. Allow sufficient time for full drainage. If coolant is clean and less than 2 years old, it may be reused after filtering.
2. 2

   Remove fan shroud
   Locate the upper fan shroud mounting bolts (typically two bolts securing shroud to radiator core support). Remove these bolts and lift the shroud up and back, allowing it to rest on the fan blades. The shroud does not need to be completely removed but must be repositioned to access radiator.
3. 3

   Disconnect upper radiator hose
   Using pliers or hose clamp pliers, loosen the hose clamp at the radiator end of the upper radiator hose. Twist the hose gently to break the seal, then pull firmly to remove from radiator neck. Be prepared for residual coolant spillage.
4. 4

   Disconnect lower radiator hose
   Access the lower radiator hose connection at the bottom of the radiator. Loosen the hose clamp and remove the hose from the radiator outlet. If the hose is seized, carefully use a flathead screwdriver to break the seal, taking care not to damage the radiator neck.
5. 5

   Disconnect transmission cooler lines
   Using a flare nut wrench, carefully loosen the transmission cooler line fittings on the passenger side of the radiator. These are typically 3/8" or 1/2" fittings. Place a drain pan beneath to catch automatic transmission fluid. Once loosened, unthread by hand and plug the lines immediately to prevent dirt entry and fluid loss.
   ⚠Use only a flare nut wrench on these fittings to prevent rounding off the soft brass or steel nuts. Standard open-end wrenches will damage the fittings.
6. 6

   Remove upper radiator mounting hardware
   Locate the two upper radiator mounting bolts or brackets at the top of the radiator core support. These typically secure the radiator to the core support via rubber-isolated mounting brackets. Remove these fasteners completely and retain hardware for reinstallation.
7. 7

   Remove radiator assembly
   Carefully lift the radiator straight up and out of the engine compartment, clearing the lower mounting pins or supports. Tilt the top toward the engine as needed to clear the fan blades and core support. Watch for any remaining hose connections or wiring to the coolant temperature sender if equipped.
8. 8

   Inspect and clean mounting area
   With the radiator removed, inspect the radiator core support for damage or rust. Clean the lower mounting saddles and remove any debris. Check the condition of the rubber mounting insulators and replace if cracked or deteriorated. Wire brush any rust from mounting surfaces.
9. 9

   Install new radiator
   Position the new radiator into the engine compartment, carefully lowering it into place. Ensure the lower mounting pins or tabs engage properly with the lower support saddles. Align the upper mounting brackets with the core support mounting holes.
10. 10

    Secure radiator mounting hardware
    Install the upper radiator mounting bolts or brackets and tighten securely, but do not overtighten as this can compress the rubber insulators excessively. Verify the radiator sits level and is not tilted in any direction.
11. 11

    Reconnect transmission cooler lines
    Install new o-rings on the transmission cooler line fittings if applicable. Thread the cooler lines into the radiator fittings by hand first to ensure proper alignment, then tighten with a flare nut wrench. Tighten firmly but do not overtighten the brass fittings.
12. 12

    Connect radiator hoses
    Install the lower radiator hose first, ensuring it is fully seated on the radiator outlet neck. Position a new hose clamp and tighten securely. Repeat for the upper radiator hose. Ensure hoses are routed without kinks and do not contact the fan blades or belts.
13. 13

    Reinstall fan shroud
    Reposition the fan shroud to its proper location around the fan assembly and against the radiator. Install the upper mounting bolts and tighten securely. Verify the shroud is properly positioned and does not contact the fan blades at any point.
14. 14

    Fill cooling system
    Close the radiator petcock. Fill the radiator with the appropriate 50/50 mixture of antifreeze and distilled water until the radiator is full to the neck. Fill the overflow reservoir to the proper level if equipped. Reconnect the negative battery cable.
15. 15

    Bleed cooling system and check for leaks
    With the radiator cap off, start the engine and allow it to warm up to operating temperature. Add coolant as the level drops during the bleeding process. Squeeze the upper radiator hose periodically to help release air pockets. Once the thermostat opens and coolant circulates, top off the radiator and install the cap. Check all connections for leaks, including transmission cooler lines.

Reassembly

1. Verify all hose clamps are properly tightened and positioned
2. Confirm fan shroud is securely mounted and properly positioned around fan
3. Double-check transmission cooler line connections for proper tightness

Verification

• Allow engine to reach full operating temperature and verify thermostat opens properly
• Check for coolant leaks at all hose connections, radiator cap, and petcock
• Inspect transmission cooler line fittings for any signs of fluid seepage
• Verify cooling fan engages properly and shroud does not contact blades
• Check coolant level after cool-down and top off as necessary
• Monitor temperature gauge during initial test drive to confirm proper cooling system operation

More procedures for this vehicle