This procedure replaces the thermostat on a 2018-2024 Toyota Camry with the 2.5L I4 engine, including coolant draining, housing removal, and system refilling.

Warnings

Tools required

Parts

• Thermostat assembly × 1 — Use OEM specification
• Thermostat housing gasket/O-ring × 1 — Usually included with thermostat
• Coolant hose clamps (if damaged) × 2 — Use OEM specification

Fluids

• Toyota Super Long Life Coolant (Pink) — 2 qt

Preparation

1. Ensure engine is completely cold (not driven for at least 2 hours)
2. Park vehicle on level surface and engage parking brake
3. Gather all tools, new thermostat assembly with gasket, and fresh coolant
4. Place coolant drain pan under radiator drain petcock
5. Remove engine splash shield if necessary for access to drain petcock

Procedure

1. 1

   Drain engine coolant
   Slowly turn the radiator cap counterclockwise to relieve any residual pressure, then remove completely. Locate the radiator drain petcock at the bottom of the radiator (driver's side). Open the petcock by turning counterclockwise and allow coolant to drain into the pan. When draining slows, close the petcock hand-tight.
2. 2

   Locate thermostat housing
   Open the hood and locate the thermostat housing on the engine block, near the front of the engine. It is connected to the lower radiator hose and has two coolant hoses attached. The housing is on the driver's side of the engine block, below the intake manifold.
3. 3

   Remove coolant hoses from thermostat housing
   Using a flathead screwdriver or hose clamp pliers, loosen the hose clamps on both coolant hoses connected to the thermostat housing. Slide the clamps away from the housing connections. Carefully twist and pull the hoses off the housing. Be prepared for residual coolant to drain out. If hoses are stuck, use a pick tool to break the seal between hose and housing.
   ⚠Coolant hoses may be stuck to the housing due to age. Do not use excessive force or pry tools directly on the housing as it may crack.
4. 4

   Remove thermostat housing bolts
   Using a 10mm socket and ratchet, remove the two bolts securing the thermostat housing to the engine block. Keep these bolts in a safe location for reinstallation. Support the housing as you remove the last bolt to prevent it from dropping.
5. 5

   Remove old thermostat and housing
   Carefully pull the thermostat housing away from the engine block. Remove the old thermostat from the housing or engine block (depending on design). Note the orientation of the thermostat with the jiggle valve or air bleed hole positioned at the top. Remove and discard the old gasket or O-ring from the housing mating surface.
6. 6

   Clean mating surfaces
   Using a plastic scraper, thoroughly clean both the engine block mating surface and the thermostat housing mating surface. Remove all old gasket material, sealant residue, and debris. Wipe surfaces clean with a shop towel. Inspect for cracks, warping, or damage. Surfaces must be completely clean and dry for proper seal.
   ⚠Do not use metal scrapers on aluminum surfaces as they can cause gouges that will lead to coolant leaks.
7. 7

   Install new thermostat
   Install the new gasket or O-ring onto the thermostat housing according to the manufacturer's instructions. Insert the new thermostat into the housing or engine block recess (depending on design) with the jiggle valve or air bleed hole positioned at the highest point (typically 12 o'clock position). Ensure the thermostat is fully seated in its recess.
8. 8

   Install thermostat housing
   Position the thermostat housing against the engine block, ensuring proper alignment with the bolt holes. Hand-thread both housing bolts to prevent cross-threading. Using a torque wrench and 10mm socket, torque the housing bolts to specification in a crisscross pattern.
   Torque spec

   Thermostat Housing Bolts15 Nm (11 lb-ft)
9. 9

   Reconnect coolant hoses
   Slide the hose clamps onto the coolant hoses if removed. Push both coolant hoses fully onto the thermostat housing nipples until they bottom out. Position the hose clamps approximately 1/4 inch from the end of each hose, over the raised bead on the housing nipple. Using a torque screwdriver or carefully with a torque wrench adapter, tighten the hose clamps to specification.
10. 10

    Refill cooling system
    Verify the radiator drain petcock is closed. If equipped, locate and open the coolant air bleed screw on the engine (typically on the thermostat housing or nearby coolant passage). Slowly pour Toyota Super Long Life Coolant (Pink) into the radiator filler neck until coolant flows from the bleed screw without bubbles. Close the bleed screw to specification. Continue filling the radiator to the base of the filler neck. Fill the coolant reservoir to the FULL line.
    ℹ️Filling slowly and using the bleed screw helps prevent air pockets in the cooling system.
11. 11

    Burp cooling system
    Install the radiator cap loosely. Start the engine and allow it to reach normal operating temperature with the heater set to maximum heat. Watch the temperature gauge to ensure it rises normally and the cooling fans cycle on. Squeeze the upper radiator hose several times to help release air pockets. After the engine reaches operating temperature and fans cycle, shut off the engine and allow it to cool for 15 minutes.
12. 12

    Top off coolant and check for leaks
    Once cooled, carefully remove the radiator cap and check the coolant level. Top off as necessary to the base of the filler neck. Check the coolant reservoir level and top off to the FULL line. Install the radiator cap fully. Inspect the thermostat housing, coolant hoses, and drain petcock for any signs of coolant leaks. Wipe all surfaces dry and start the engine again briefly to verify no leaks under pressure.

Reassembly

1. Reinstall engine splash shield if removed during preparation
2. Properly dispose of old coolant according to local environmental regulations
3. Keep the old thermostat for comparison with replacement part to verify correct application

Verification

• Start the engine and verify it reaches normal operating temperature within 5-10 minutes
• Confirm the upper radiator hose becomes hot after the thermostat opens, indicating proper coolant flow
• Verify cooling fans cycle on and off automatically as designed
• Check that the heater produces hot air at idle and under load
• Inspect all connections for coolant leaks with the engine at operating temperature
• Verify coolant level remains stable in the reservoir after several drive cycles
• Monitor temperature gauge over the next few days to ensure it operates in the normal range

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