Replace the coolant bypass pipe that routes coolant between the engine block and thermostat housing on the 2019-2024 Toyota RAV4 2.5L I4 engine.

Warnings

Tools required

Parts

• Coolant bypass pipe × 1 — 16268-0V010 or equivalent
• Bypass pipe O-rings/gaskets × 1 — Included with pipe or separate
• Radiator drain plug washer × 1 — Use OEM specification

Fluids

• Toyota Super Long Life Coolant (Pink) — 10 qt

Preparation

1. Ensure engine is completely cold to the touch (at least 2 hours after last operation)
2. Park vehicle on level ground and engage parking brake
3. Place drain pan under radiator drain plug location
4. Remove engine splash shield if equipped (14mm bolts)
5. Locate the radiator drain plug on the driver's side bottom tank of the radiator

Procedure

1. 1

   Drain engine coolant
   Slowly turn the radiator cap counterclockwise to release any residual pressure, then remove completely. Locate the radiator drain plug at the bottom of the driver's side radiator tank. Remove the drain plug and allow coolant to drain into the pan. Once drained, reinstall the drain plug with a new washer.
   Torque spec

   Coolant Drain Plug15 Nm (11 lb-ft)
2. 2

   Remove air intake components
   Disconnect the air intake duct from the throttle body by loosening the hose clamp. Remove the air filter box cover and filter element. Unbolt the air filter box housing (10mm bolts) and set aside to improve access to the bypass pipe area.
3. 3

   Access the bypass pipe
   Locate the coolant bypass pipe on the driver's side of the engine between the engine block and thermostat housing. It is a metal pipe with two mounting bolts and connects to rubber hoses at both ends. Use a flashlight to inspect the entire pipe routing.
4. 4

   Disconnect coolant hoses
   Use hose clamp pliers or a flathead screwdriver to loosen the hose clamps securing the coolant hoses to both ends of the bypass pipe. Slide the clamps back away from the pipe ends. Gently twist and pull the hoses off the pipe fittings. Expect residual coolant to drain out.
5. 5

   Remove bypass pipe mounting bolts
   Remove the two mounting bolts securing the bypass pipe to the engine block and thermostat housing area. These are typically 10mm or 12mm bolts. Keep track of bolt locations as they may be different lengths.
6. 6

   Remove old bypass pipe
   Carefully maneuver the bypass pipe out of its position. The pipe may require slight rotation or angling to clear surrounding components. Inspect the pipe for cracks, corrosion, or leaks that necessitated replacement.
7. 7

   Prepare new bypass pipe
   Inspect the new bypass pipe and verify it matches the old unit exactly. Install new O-rings or gaskets onto the pipe fittings if not pre-installed. Lightly lubricate the O-rings with clean coolant to aid installation.
8. 8

   Install new bypass pipe
   Position the new bypass pipe into place, aligning the mounting bolt holes with the engine block and thermostat housing. Install the mounting bolts finger-tight first to ensure proper alignment. Torque the mounting bolts to specification.
   Torque spec

   Housing Bolts14 Nm (10 lb-ft)
9. 9

   Reconnect coolant hoses
   Push the coolant hoses firmly onto both ends of the new bypass pipe until fully seated. Slide the hose clamps into position over the hose-to-pipe connection points. Tighten the hose clamps securely.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
10. 10

    Reinstall air intake components
    Reinstall the air filter box housing and secure with mounting bolts. Replace the air filter element and cover. Reconnect the air intake duct to the throttle body and tighten the hose clamp.
11. 11

    Refill cooling system
    Locate the coolant reservoir and the radiator fill neck. Open the bleed screw on top of the thermostat housing or at the highest point of the cooling system. Slowly fill the radiator through the radiator neck with Toyota Super Long Life Coolant until coolant flows from the bleed screw without air bubbles. Close the bleed screw. Continue filling until the radiator is full, then fill the reservoir to the FULL line.
    Torque spec

    Bleed Screw7 Nm (5 lb-ft)
12. 12

    Burp the cooling system
    Install the radiator cap loosely. Start the engine and let it idle with the heater on maximum temperature setting. Monitor coolant level in the reservoir as the engine warms up and the thermostat opens. Add coolant to the reservoir as needed to maintain proper level. Once engine reaches operating temperature and the cooling fans cycle on, check for leaks around the bypass pipe.
    ⚠Keep hands and tools clear of the radiator fan which may start at any time when the engine is running.
13. 13

    Final bleed and top-off
    After the engine has reached operating temperature, shut off the engine and allow it to cool for 15 minutes. Carefully remove the radiator cap and check the coolant level. Top off the radiator if needed. Ensure the reservoir is at the FULL cold line. Install the radiator cap securely. Reinstall the engine splash shield if removed.

Reassembly

1. Verify all hose clamps are properly tightened and positioned
2. Double-check that the bleed screw is closed after final bleeding procedure
3. Confirm air intake system is fully reconnected and sealed
4. Wipe down any coolant spills from engine components to prevent false leak diagnosis

Verification

• Start the engine and verify no coolant leaks from the bypass pipe connections or mounting points
• Confirm engine reaches normal operating temperature (approximately 195°F) and cooling fans operate normally
• Check coolant reservoir level after engine cools and top off if necessary to FULL cold line
• Test drive the vehicle and monitor temperature gauge for normal operation
• Re-check for leaks after test drive and verify coolant level remains stable

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