Transmission Oil Cooler

Replace the transmission oil cooler on a 2018-2024 Honda Accord 1.5L Turbo CVT, including disconnecting cooler lines, removing the cooler assembly, and refilling transmission fluid.

Warnings

Tools required

Parts

• Transmission oil cooler assembly × 1 — Use OEM Honda specification
• Transmission drain plug crush washer × 1 — 94109-20000 or equivalent
• Transmission cooler line O-rings × 2 — Use OEM Honda specification

Fluids

• Honda DW-1 ATF — 4 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow engine and transmission to cool for at least 30 minutes if recently driven
3. Raise front of vehicle and support securely on jack stands
4. Remove engine under cover and splash shields for access
5. Place drain pan under transmission drain plug

Procedure

1. 1

   Drain transmission fluid
   Remove the transmission drain plug using a 17mm socket and allow fluid to drain completely into the drain pan. Inspect the drain plug crush washer and replace with new. Set aside drain plug with new crush washer for reinstallation.
   Torque spec

   Transmission Drain Plug30 Nm (22 lb-ft)
2. 2

   Access transmission oil cooler
   Locate the transmission oil cooler integrated into the lower section of the radiator assembly on the driver's side. Identify the two transmission cooler lines connecting to the cooler (supply and return lines). Clean the area around the line connections to prevent contamination.
3. 3

   Disconnect cooler supply line
   Using the appropriate line disconnect tool, release the quick-connect fitting on the upper transmission cooler line (supply line). Press the release tabs while pulling the line straight out from the cooler. Cap or plug the line immediately with a clean plastic bag and zip tie to prevent contamination. Expect residual fluid spillage.
   ⚠Do not bend or kink transmission cooler lines during removal. Damaged lines must be replaced.
4. 4

   Disconnect cooler return line
   Using the line disconnect tool, release the quick-connect fitting on the lower transmission cooler line (return line). Remove the line from the cooler connection and cap or plug immediately. Allow any remaining fluid to drain into the pan.
5. 5

   Remove transmission oil cooler mounting bolts
   Remove the transmission oil cooler mounting bolts securing the cooler assembly to the radiator or chassis. The cooler may be secured with 10mm or 12mm bolts depending on mounting configuration. Note the location and length of each bolt for proper reassembly.
   ℹ️Some models may have the cooler integrated directly into the radiator. If cooler cannot be separated, consult service manual for radiator removal procedure.
   Torque spec

   Mounting Bolts26 Nm (19 lb-ft)
6. 6

   Remove old transmission oil cooler
   Carefully remove the transmission oil cooler assembly from the vehicle. Inspect mounting brackets and hardware for damage or corrosion. Clean the mounting surface thoroughly.
7. 7

   Install new transmission oil cooler
   Position the new transmission oil cooler assembly in place, ensuring proper alignment with mounting points and line connection ports. Install mounting bolts finger-tight initially to allow adjustment. Verify cooler orientation matches the original installation with supply line port at top.
8. 8

   Torque cooler mounting bolts
   Tighten the transmission oil cooler mounting bolts to specification using a torque wrench. Use 26 Nm (19 lb-ft) for smaller mounting hardware. Verify cooler is secure and properly aligned with line connection points.
   Torque spec

   Mounting Bolts26 Nm (19 lb-ft)
9. 9

   Reconnect transmission cooler lines
   Install new O-rings on both transmission cooler line fittings, lubricating lightly with clean ATF. Connect the supply line (upper) and return line (lower) to the cooler, pushing firmly until you hear/feel a positive click. Pull back on each line to verify secure connection.
   ⚠Ensure O-rings are properly seated and lines are clicked into place. Loose connections will cause fluid leaks and potential transmission damage.
10. 10

    Reinstall transmission drain plug
    Install the transmission drain plug with new crush washer. Torque to specification using a torque wrench.
    Torque spec

    Transmission Drain Plug30 Nm (22 lb-ft)
11. 11

    Refill transmission fluid
    Remove the transmission dipstick (located near the front of the engine bay). Using a funnel, add 3.5 quarts of Honda DW-1 ATF through the dipstick tube initially. Start the engine and allow to idle for 2-3 minutes. With engine running and transmission in Park, check fluid level on dipstick. Add additional fluid in 0.5 quart increments until level reaches the lower mark.
    ⚠️Engine must be running when checking CVT fluid level. Check with transmission in Park on level ground.
12. 12

    Cycle transmission through gears
    With engine at operating temperature and foot on brake, shift transmission through all gear positions (P-R-N-D-S-L), pausing 2-3 seconds in each position. Return to Park and recheck fluid level. Add fluid as needed to bring level to the upper mark on the dipstick.

Reassembly

1. Reinstall engine under covers and splash shields
2. Lower vehicle from jack stands
3. Dispose of old transmission fluid and oil cooler according to local regulations

Verification

• Start engine and verify no transmission fluid leaks at cooler connections or drain plug
• Allow engine to reach operating temperature and recheck transmission fluid level with engine running
• Test drive vehicle through all gears and verify normal transmission operation
• After test drive, recheck fluid level and inspect cooler connections for any seepage
• Monitor transmission fluid level and condition over the next few days of driving

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