Radiator Hose - Upper

This procedure covers removal and replacement of the upper radiator hose on the 2018-2024 Honda Accord 1.5L turbo engine, including coolant draining and refilling.

Warnings

Tools required

Parts

• Upper radiator hose × 1 — Use OEM specification
• Hose clamps (if original clamps are damaged) × 2 — Use OEM specification

Fluids

• Honda Type 2 Coolant (Blue) — 3 qt

Preparation

1. Ensure the engine is completely cool to the touch
2. Park vehicle on level ground and engage parking brake
3. Open the hood and locate the upper radiator hose connecting the engine thermostat housing to the radiator upper tank

Procedure

1. 1

   Drain the cooling system
   Place a drain pan under the radiator. Slowly turn the radiator cap counterclockwise to release any residual pressure, then remove it completely. Locate the radiator drain plug on the lower driver's side of the radiator. Open the drain plug and allow coolant to drain into the pan. You do not need to drain the entire system, but draining 2-3 quarts will prevent significant spillage.
2. 2

   Remove engine cover (if equipped)
   If your Accord has a plastic engine cover, lift it upward from the rear clips first, then pull forward to release the front tabs. Set aside. This provides better access to the upper radiator hose connection at the thermostat housing.
   Torque spec

   Cover Screws10 Nm (8 lb-ft)
3. 3

   Loosen radiator-side hose clamp
   Locate the spring-type or worm-gear clamp securing the upper radiator hose to the radiator neck. If it's a spring clamp, use hose clamp pliers to compress and slide it back on the hose away from the radiator. If it's a worm-gear clamp, use a flathead screwdriver to loosen it and slide it back approximately 2-3 inches from the connection point.
4. 4

   Loosen thermostat housing-side hose clamp
   Locate the clamp at the engine side where the upper hose connects to the thermostat housing near the cylinder head. Loosen or compress this clamp and slide it back on the hose away from the connection point. Note the orientation of the hose for installation.
5. 5

   Remove the upper radiator hose
   Twist the hose gently while pulling to break the seal at both connection points. Remove the hose from the radiator first, allowing any residual coolant to drain into your drain pan. Then remove the engine side. Expect some coolant spillage; have shop towels ready.
6. 6

   Inspect and clean connection points
   Inspect the radiator neck and thermostat housing connection points for cracks, corrosion, or damage. Clean both surfaces with a shop towel to remove old coolant residue and ensure a proper seal for the new hose. Check that the thermostat housing is not cracked.
7. 7

   Install new upper radiator hose
   Slide the new hose clamps onto the new hose before installation (if using new clamps). Position the hose onto the thermostat housing first, ensuring it seats fully onto the connection neck. Then connect the radiator side, ensuring both ends are fully seated with no gaps between the hose and the connection points.
8. 8

   Tighten hose clamps
   Position each clamp approximately 1/4 inch from the end of each hose connection. Tighten worm-gear clamps to specification using a torque wrench, or ensure spring clamps are positioned correctly in their groove and fully engaged. Verify the hose cannot be twisted or pulled off by hand.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
9. 9

   Close radiator drain and refill coolant
   Close and tighten the radiator drain plug. Fill the radiator with Honda Type 2 (blue) coolant until it reaches the base of the radiator neck. Fill the coolant reservoir to the MAX line. Do not mix coolant types.
10. 10

    Bleed air from cooling system
    With the radiator cap still off, start the engine and let it idle. Turn the heater to maximum temperature and fan speed. As the engine warms, the thermostat will open and coolant level will drop. Add coolant as needed to maintain level. Watch for circulation and bubbles. Run until the cooling fan cycles on, then turn off the engine.
11. 11

    Final coolant level check
    After the engine cools for 10-15 minutes, recheck the radiator coolant level and top off if needed. Install the radiator cap by aligning the tab and turning clockwise until it clicks. Verify the coolant reservoir is at the MAX line. Wipe up any spilled coolant.

Reassembly

1. Reinstall engine cover if equipped, ensuring all clips engage properly
2. Inspect the area under the vehicle for any coolant leaks from the drain plug

Verification

• Start the engine and let it reach operating temperature while monitoring for leaks at both hose connections
• Check that the upper radiator hose becomes hot to the touch, indicating proper coolant circulation
• Verify no coolant drips or seepage at either clamp location after a 10-minute test drive
• Recheck coolant reservoir level after the first drive cycle and top off if necessary
• Monitor coolant level over the next few days to ensure no slow leaks are present

More procedures for this vehicle