Coolant Reservoir

Replacement of the engine coolant reservoir tank on the 2016-2021 Honda Civic 1.5L Turbo, including draining and refilling the cooling system.

Warnings

Tools required

Parts

• Coolant reservoir tank × 1 — 19101-5AA-A01
• Reservoir cap (if damaged) × 1 — Use OEM specification

Fluids

• Honda Type 2 Coolant (Blue) — 1.5 qt

Preparation

1. Ensure engine is completely cold to the touch
2. Park vehicle on level ground and engage parking brake
3. Open hood and locate coolant reservoir on driver side of engine bay near firewall
4. Place drain pan beneath radiator drain petcock location

Procedure

1. 1

   Relieve cooling system pressure
   Slowly rotate the coolant reservoir cap counterclockwise to the first detent and allow pressure to escape. Wait until hissing stops, then remove cap completely.
2. 2

   Drain coolant from system
   Locate the radiator drain petcock on the bottom of the radiator. Open the petcock and drain coolant into the drain pan until level drops below the reservoir connection point. This will take approximately 1-2 quarts. Close the petcock hand tight.
   Torque spec

   Drain Petcock6 Nm (5 lb-ft)
3. 3

   Disconnect reservoir hose
   Locate the single coolant hose connecting to the bottom of the reservoir. Use pliers to compress and slide the hose clamp away from the reservoir connection point. Twist and pull the hose off the reservoir nipple. Some residual coolant will drain.
4. 4

   Remove reservoir mounting bolts
   Using a 10mm socket, remove the two mounting bolts securing the reservoir to the body. The bolts are located at the top and bottom of the reservoir bracket on the driver side.
   Torque spec

   Reservoir Mounting Bolts8 Nm (6 lb-ft)
5. 5

   Remove reservoir tank
   Lift the reservoir upward and out of the engine bay. Tilt it to drain any remaining coolant into the drain pan. Inspect the reservoir for cracks, especially around the mounting points and hose connection.
6. 6

   Install new reservoir
   Position the new coolant reservoir into the mounting bracket, aligning the bolt holes. Install both mounting bolts finger tight, then torque to specification using a torque wrench.
   Torque spec

   Reservoir Mounting Bolts8 Nm (6 lb-ft)
7. 7

   Reconnect coolant hose
   Push the coolant hose firmly onto the reservoir nipple until it seats completely. Slide the hose clamp into position over the connection point, approximately 10mm from the end of the hose. Torque the clamp to specification.
   Torque spec

   Hose Clamps4 Nm (3 lb-ft)
8. 8

   Refill cooling system
   Fill the reservoir to the MAX line with Honda Type 2 Blue coolant. Start the engine and allow it to reach operating temperature with the heater on maximum. Monitor coolant level and add as needed. The level will drop as air purges from the system.
9. 9

   Bleed cooling system
   With engine at operating temperature, locate the coolant bleed screw on top of the thermostat housing. Loosen the bleed screw until coolant flows without air bubbles, then tighten to specification. Top off reservoir to MAX line.
   Torque spec

   Bleed Screw6 Nm (5 lb-ft)

Reassembly

1. Install reservoir cap by turning clockwise until it clicks into place
2. Wipe down any spilled coolant from engine bay components
3. Dispose of used coolant properly at a recycling center or auto parts store

Verification

• Check that coolant level is at MAX line on cold reservoir
• Start engine and verify no leaks at reservoir hose connection
• Allow engine to reach operating temperature and verify coolant circulates properly
• Check that heater blows hot air at idle
• After first drive cycle, recheck coolant level when engine is cold and top off if necessary

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