Contents: Examination ⇊ Replacement ⇊
Warning! Do not open the radiator cap or remove the thermostat until the engine has cooled down completely! See also warning at the beginning Antifreeze - general information.
Examination
1. Before you finally confirm that the thermostat is out of order, check the coolant level in the system, the condition and tension of the drive belt (see Chapter Routine maintenance), as well as the proper functioning of the temperature meter.
2. One of the possible reasons for the engine warming up too slowly (according to the meter readings, the thermostat is stuck in the open position). Replace the thermostat with a new one.
3. If the engine overheats, feel the upper radiator hose with your hand. If the hose is not hot, the thermostat may be stuck in the closed position, blocking the circulation of coolant through the radiator. Replace the thermostat.
Attention! Never operate the vehicle with the thermostat removed! This may disrupt the feedback of the on-board processor, which will lead to increased toxicity of exhaust gases and increased fuel consumption.
4. If the upper hose is hot, it means that coolant is circulating through the radiator, i.e. the thermostat is open. Refer to the materials Diagnostics of faults in vehicle components and systems.
Replacement
1. Disconnect the negative cable from the battery.
Warning! If the car stereo system is equipped with a security code, make sure you have the correct combination to activate the audio system before disconnecting the battery!
2. Drain the coolant from the radiator (see Chapter Routine maintenance). If the mixture has been changed recently, save it for future use.
3. Follow the upper radiator hose to the engine and locate the thermostat housing cover.
4. Loosen the clamp and remove the hose from its connecting pipe. If the hose is "stuck", grab it with pliers (as close to the end as possible) and try to rotate it on the branch pipe in order to destroy the retaining layer. the old hose to be replaced can be simply cut (try not to scratch the pipe).
5. If the surface of the branch pipe that contacts the hose is corroded or mechanically damaged, it makes sense to replace the thermostat housing cover.
6a. Disconnect the electrical connector of the engine coolant temperature (ECT) sensor, unscrew the mounting bolts and remove the thermostat housing cover (Honda Civic). If the lid is stuck, tap it with a soft-faced hammer. Be prepared to collect any spilled liquid.
6b. Location of mounting bolts (Acura Integra).
7. Try to remember the thermostat setting (thumbs up), then remove it from the casing.
8. Replace the thermostat rubber seal (see accompanying illustration).
9. Install the thermostat into the housing (do not use any sealant). Make sure it is turned with the finger facing up and the spring-loaded side facing the engine (see accompanying illustration).
10. Replace the cover and secure it with the bolts, tightening them to the required torque.
11. Connect the hose to the cover pipe and secure it securely with a clamp. Replace all components removed for access.
12. Fill the system with the required amount of coolant (see Chapter Routine maintenance).
13. Start the engine and check for leaks and proper functioning of the thermostat (see paragraphs 2 through 4).