Subaru Legacy/Outback

1999-2003 of release

Repair and operation of the car

Subaru of Legasi, Autbek
+ Cars Subaru Legacy, Outback
+ Operation manual
+ Routine maintenance
+ Engine
- Cooling systems, heating
   - Engine cooling system
      Antifreeze - general information
      Detachment and replacement of hoses of the cooling system
      Service of the cooling system (depletion, washing and filling)
      Details of installation and principle of functioning of fans of the cooling system
      The water pump - the general information
      Check of serviceability of functioning and replacement of the thermostat
      Check of serviceability of functioning, removal, service and installation of fans of the cooling system
      Service, removal and installation of a radiator of the cooling system
      Check of a condition of a cover of a radiator
      Removal and installation of a broad tank
      Removal, check and installation of the water pump
   + Systems of heating/ventilation/air conditioning
+ Power supply system and release
+ Electric equipment of the engine
+ Manual box and differential
+ Automatic transmission
+ Coupling
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment


Check of serviceability of functioning and replacement of the thermostat

Thermostat design

1 — the Valve
2 — the Spring
3 — the Emphasis
4 — the Piston
5 — Directing

6 — the Rubber holder
7 — the Lock ring
8 — the Voskozapolnenny element
9 — the pumping Valve

The basis of a design of the thermostat is made by the tight thermosensitive element filled with wax granules, which volume from changes with change of temperature. Opening and closing of the working valve of the thermostat happens strictly at certain values of temperature.



1. Before finally being approved in opinion on a thermostat exit out of operation, check liquid level in the cooling system, a state and effort of a tension of a driving belt (see the Head Routine maintenance), and also serviceability of functioning of the measuring instrument / a control lamp of temperature.
2. One of the possible reasons of insufficiently fast warming up of the engine (according to indications of the measuring instrument) is jamming of the thermostat in open situation. Replace the thermostat new (see below).
3. In case of an overheat of the engine touch the lower hose of a radiator. If the hose is not heated, possibly, the thermostat is jammed in a closed position and blocks circulation of cooling liquid through a radiator. Replace the thermostat.

 Do not operate the car with the removed thermostat at all, - thus feedback of the onboard processor that will lead to increase of toxicity of the fulfilled gases and excessive increase in fuel consumption can be broken!

4. If the lower hose is heated, it means that cooling liquid regularly circulates through a radiator, i.e. the thermostat is open, - address to materials of the Section devoted to diagnostics of malfunctions of the cooling system (see Introduction at the beginning of the present manual).
5. The most exact results are yielded by check of the thermostat on a workbench.
6. Remove the thermostat from the engine (see below).

7. Tie up a piece of a wire to assembly of the thermostat and lower it in the capacity filled with water, there lower the thermometer.

 Track that the thermometer and the thermostat did not adjoin to walls and a bottom of capacity.

1 — the Thermometer
2 — the Thermostat

8. Start warming up slowly water, watching change of indications of the thermometer, - operation of the valve of the thermostat has to happen in strict accordance with requirements of Specifications.

9. Estimate the size of full opening of the valve, - the nominal rate makes 8 mm.



1. Disconnect a negative wire from the battery.
2. Remove protection of a case.
3. Empty the cooling system (see the Head Routine maintenance).
4. Disconnect a radiator hose from a thermostat cover.

5. Uncover the thermostat and sealing laying, take the thermostat from a casing, - try to remember its adjusting situation. Carefully smooth out sealing surfaces of a cover and a casing of the thermostat a scraper, then wipe their rags moistened in solvent.

6. Installation is made upside-down. Do not forget to replace sealing laying, track that the thermostat was installed by the pumping valve forward. The effort of a tightening of bolts of fastening of a cover makes 6.4 Nanometers.

7. In summary fill the cooling system (see the Head Routine maintenance), start the engine and check it for existence of signs of development of leaks. Make sure of serviceability of functioning of the thermostat.