Genuine Honda Civic Thermostat

Honda Civic Thermostat Parts Questions & Answers

• Thermostat Assembly (Fuji Seiko)
  19301-RNA-315
  Q: How do you disconnect the cable from the negative battery terminal and drain the cooling system while replacing the thermostat in Honda Civic?

  A: Disconnect the cable from the negative battery terminal and drain the cooling system, saving the coolant if it is in good condition. For a Civic with a 2.4L engine or a 2014 and earlier CR-V, access the thermostat from the underside of the engine compartment by raising the front of the vehicle and removing the under-vehicle splash shield. For a 1.8L Civic or a 2015 and later CR-V, access the thermostat from the top of the engine compartment, removing the PCM and bracket on CR-V models. On 1.8L models, use pliers to squeeze the upper radiator hose clamp, slide it up, and remove the hose, twisting if necessary. Locate the thermostat housing cover by following the lower radiator hose to the engine, then loosen the hose clamp and detach the hose. If the fitting is deteriorated, it may need replacement. On 1.8L models, move the harness bracket out of the way, then remove the thermostat cover bolts and detach the housing cover, tapping it if stuck. Note the jiggle pin's position when removing the thermostat, as it should be at the top. For 2.4L engines, replace the thermostat cover and thermostat as one assembly. Clean all old gasket material from the housing and cover, then install a new rubber seal over the thermostat on 1.8L engines, ensuring proper alignment. For 2.4L engines, install a new O-ring into the housing. Install the thermostat in the housing without sealant, ensuring the jiggle pin is at the top. Install the housing cover or thermostat assembly and tighten the bolts to the specified torque. Reattach the hose and tighten the clamp securely, then reinstall all components removed for access. Refill the cooling system and reconnect the battery. Start the engine, allowing it to reach normal operating temperature, then check for leaks and proper thermostat operation.