Attention! Do not open the radiator cap and do not remove the thermostat until the engine has completely cooled down! See also the warning at the beginning Antifreeze - general information.
Examination
1. Before finally confirming that the thermostat is out of order, check the coolant level in the system, the condition and tension of the drive belt (see chapter Current service), as well as the correct functioning of the temperature meter.
2. One of the possible reasons for the engine warming up too slowly (according to the readings of the meter, 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 closed, cutting off coolant circulation through the radiator. Replace thermostat.
Attention! Never operate the vehicle with the thermostat removed! In this case, the feedback of the onboard processor may be broken, which will lead to an increase in the toxicity of exhaust gases and an increase in fuel consumption.
4. If the upper hose is hot, it means that the coolant is circulating through the radiator, i.e. thermostat is open. Refer to materials Diagnostics of malfunctions of nodes and systems of the car.
Replacement
1. Disconnect the negative cable from the battery.
Attention! If the stereo system installed in the car is equipped with a security code, before disconnecting the battery, make sure that you have the correct combination to activate the audio system!
2. Drain the coolant from the radiator (see chapter Current service). If the mixture has been changed recently, save it for future use.
3. Walk along the upper radiator hose to the engine and find the thermostat housing cover.
4. Loosen the clamp and remove the hose from its connecting pipe. If the hose "stuck", grab it with tongs (as close to the end as possible) and try to rotate on the nozzle 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 nozzle in contact with the hose is corroded or mechanically damaged, it makes sense to replace the thermostat housing cover.
6a. Disconnect the engine coolant temperature sensor electrical connector (EATING), turn out fixing bolts and remove a cover of a casing of the thermostat (Honda Civic). If cover "got used to", tap it with a soft-faced hammer. Prepare to collect spilled liquid.
6b. The location of the mounting bolts (Acura Integra).
7. Try to remember the installation position of the thermostat (thumbs up), then remove it from the case.
8. Replace thermostat rubber seal (see accompanying illustration).
9. Install the thermostat in the casing (do not use any sealant). Make sure that it is turned with a finger up, and with the spring-equipped side towards the engine (see accompanying illustration).
10. Replace the cover and secure it with bolts, tightening the latter to the required torque.
11. Connect a hose to the cover branch pipe and secure it firmly with a clamp. Replace all components removed for access.
12. Fill the system with the required amount of coolant (see chapter Current service).
13. Start the engine and check for leaks and thermostat operation (see paragraphs 2 to 4).