Engine Oil Cooler

This procedure covers the removal and installation of the engine oil cooler on a 1970 AMC Rebel Machine with 390ci V8 engine.

Warnings

Tools required

Parts

• Engine oil cooler assembly × 1 — Use OEM specification or performance equivalent
• Oil cooler mounting gaskets/O-rings × 1 — Use OEM specification
• Oil cooler line crush washers or seals × 2 — Use OEM specification
• Engine oil filter × 1 — FL-1A or equivalent
• Engine oil × 5 — SAE 10W-40 or 10W-30
• Coolant × 2 — Ethylene glycol 50/50 mix

Fluids

• Engine oil (SAE 10W-40 or 10W-30) — 5 qt
• Engine coolant (50/50 mix) — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely for at least 2 hours
3. Raise front of vehicle and support securely on jack stands
4. Remove engine splash shield or belly pan if equipped
5. Disconnect negative battery cable
6. Place drain pan beneath oil pan drain plug
7. Place separate drain bucket beneath radiator drain cock

Procedure

1. 1

   Drain engine oil
   Remove the oil pan drain plug using appropriate socket and allow oil to drain completely into the drain pan. Wipe drain plug threads clean and set aside with drain plug washer.
2. 2

   Drain coolant partially
   Open the radiator drain cock and drain approximately 2 quarts of coolant into the drain bucket. This will lower the coolant level below the oil cooler to minimize spillage. Close the drain cock when level is sufficiently low.
3. 3

   Remove oil filter
   Using the oil filter wrench, remove the engine oil filter by turning counterclockwise. Allow remaining oil to drain from the filter adapter. Clean the filter mounting surface on the adapter with a shop rag.
4. 4

   Disconnect oil cooler lines
   Using line wrenches to prevent rounding, carefully disconnect the oil cooler inlet and outlet lines at the cooler. These are typically threaded fittings with crush washers. Be prepared for residual oil and coolant drainage. Cap or plug the lines to prevent contamination.
5. 5

   Remove oil cooler mounting bolts
   Locate the oil cooler mounting bolts securing the cooler to the engine block or oil filter adapter. Typically there are 2-4 bolts depending on the cooler configuration. Remove these bolts and retain them if in good condition.
6. 6

   Remove oil cooler assembly
   Carefully pull the oil cooler assembly away from the engine block. It may be stuck due to gasket adhesion. Gently work it free, taking care not to damage the mounting surface. Remove and discard the old gasket or O-ring seals.
7. 7

   Clean mounting surfaces
   Using a wire brush and shop rags, thoroughly clean the oil cooler mounting surface on the engine block. Remove all traces of old gasket material, oil residue, and corrosion. The surface must be completely clean and smooth for proper sealing.
8. 8

   Inspect oil passages
   Inspect the oil passages in the engine block for debris or blockage. Clean if necessary. Check the threaded holes for the mounting bolts and chase threads if needed to ensure proper torque application.
9. 9

   Install new oil cooler
   Position new gaskets or O-rings on the new oil cooler assembly. Align the cooler with the mounting holes and oil passages on the engine block. Start all mounting bolts by hand to ensure proper alignment before tightening.
10. 10

    Tighten oil cooler mounting bolts
    Tighten the oil cooler mounting bolts in a crisscross pattern evenly. Since specific torque values are not provided, tighten to manufacturer recommendations (typically 15-25 ft-lbs for this application). Do not overtighten as this can distort the cooler or crack the mounting surface.
11. 11

    Reconnect oil cooler lines
    Install new crush washers or seals on the oil cooler line fittings. Thread the inlet and outlet lines into the oil cooler by hand first to avoid cross-threading. Tighten securely with line wrenches, typically to 20-30 ft-lbs or until snug plus 1/4 turn.
12. 12

    Install new oil filter
    Apply a thin film of clean engine oil to the rubber gasket on the new oil filter. Thread the filter onto the adapter by hand until the gasket contacts the mounting surface, then tighten an additional 3/4 turn. Do not use the filter wrench for installation.
13. 13

    Reinstall oil drain plug
    Install the oil pan drain plug with its washer (replace washer if damaged). Tighten to typical specification of 25-30 ft-lbs for AMC 390 oil pan plugs.
14. 14

    Refill engine oil and coolant
    Lower the vehicle from jack stands. Refill the engine with the appropriate quantity and grade of engine oil (typically 5 quarts for the AMC 390). Refill the cooling system with coolant to the proper level. Install the oil filler cap and radiator cap.

Reassembly

1. Reinstall engine splash shield or belly pan if previously removed
2. Reconnect negative battery cable
3. Double-check all connections and fasteners for tightness
4. Ensure no tools or parts are left in the engine compartment

Verification

• Start the engine and allow it to idle, checking immediately for oil leaks around the cooler, lines, and filter
• Monitor the oil pressure gauge to ensure normal pressure (30-60 psi at idle when warm for AMC 390)
• Allow engine to reach operating temperature and check for coolant leaks at the oil cooler
• Shut off engine, wait 5 minutes, then check oil level on dipstick and top off if necessary
• Check coolant level and top off as needed
• Inspect under vehicle for any oil or coolant drips
• Test drive vehicle and recheck all fluid levels and connections after the first drive cycle

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