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
   + 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


Cooling systems, heating

General information and precautionary measures

Engine cooling system

The scheme of circulation of cooling liquid on the example of the 6-cylinder engine

1 — the Water pump
2 — the Oil cooler
3 — the Right head of cylinders
4 — the Block of cylinders

5 — the Left head of cylinders
6 — the throttle Case
7 — the Thermostat

Scheme of the organization of heating/ventilation of salon

1 — the Forward deflector of an air duct of an obduv of a windshield
2 — Lateral deflectors of an air duct of an obduv of a windshield
3 — Deflectors of the central air duct of the dashboard
4 — Deflectors of lateral air ducts of the dashboard
5 — Forward deflectors of the lower air duct
6 — Back deflectors of the lower air duct
7 — Fresh air
8 — air circulation Streams
9 — the Ventilating gate

10 — the Gate of the lower air duct
11 — the Gate of an air duct of an obduv of a windshield
12 — the Mixing gate
13 — Inlet gates
14 — the heater Heat exchanger
15 — the Evaporator (models with To/in)
16 — the heater Fan
17 — the Filter (an additional complete set)

Servo-driver of management of functioning of regime gates

1 — Having blown in a windshield
2 — Having blown in glass/heating of salon

3 — Heating of salon
4 — Ventilation/heating of salon

All models of the cars considered in the present manual are equipped with the engine cooling system working with an excessive pressure with thermostatic management of circulation of working liquid. The water pump of rotor type is fixed on the left semi-block of the engine (l models 2.0 and 2.5), or placed in the casing formed by deepenings in a back cover of the GRM drive and the top section of the pallet of a case (model of 3.0 l) and provides pumping of cooling liquid through a cooling path of the power unit (see the Section the Water pump - the general information). The drive of the water pump is carried out from a gas-distributing belt / chain. The stream of liquid washes the regions of an arrangement of each of cylinders in the block laid in molding of semi-blocks and heads of cylinders cooling channels provide intensive cooling of inlet and final ports, areas of installation of spark plugs and the directing plugs of final valves. The cooling system from the moment of start of the engine passes through three modes of functioning: at the first stage until that the peratura of cooling liquid rose above 76 °C, the thermostat remains closed and liquid circulates on a small circle from which working contour the radiator is excluded that provides a fast warming up of the engine; at a temperature of 76 ÷ 80 °C the thermostat opens and the contour of circulation joins a radiator; on reaching temperature of cooling liquid of value of 95 °C (4-cylinder engines) of/91 °C (6-cylinder engines) of ECM, being guided by indications of the sensor of temperature of cooling liquid (ECT), gives out command for activation of the fan(s) of the cooling system, forced which the additional air stream considerably increases efficiency of functioning of the heat exchanger of a radiator.

The Voskozapolnenny thermostat is built in an inlet branch pipe of the water pump and controls the working temperature of the engine in the course of its warming up. The first minutes after start of the cold engine the thermostat remains closed, preventing thereby circulation of cooling liquid through a radiator. In process of approach of temperature of the engine to normal working value, the thermostat valve gradually opens, connecting to a cooling contour the radiator providing the maximum intensity of the heat sink from a working body (cooling liquid).


The cooling system has a tight design and is densely closed by the cover of a radiator capable to maintain excessive pressure that provides increase of a boiling point of cooling liquid and, respectively, efficiency of the heat sink through a radiator. At excess by internal pressure in system of some certain value, the sprung plate of the radiator of the safety valve which is built in in a cover rises over the saddle, providing an overflowing of excess of cooling liquid on a connecting (overflow) tube in a broad tank. In process of cooling of system liquid automatically comes back from a tank to a radiator.

Dolivaniye of cooling liquid in system is made through a mouth of a broad tank which at the same time acts also as the receiver accumulating in itself the excess of the liquid extending at a warming up which is forced out from a radiator.

In view of the listed features of a design, such cooling system received the name closed as in it any functional losses of a working body are excluded.

Systems of heating/ventilation/air conditioning (HVAC)

System of heating/ventilation of salon

The main components of system of heating/ventilation of salon are the electric fan and the heat exchanger, and also system of air ducts of distribution of an air stream placed in the box-shaped casing of a heater fixed under the dashboard. The cooling liquid warmed in the engine circulates via the heater heat exchanger, giving the to the air which is warmly filling a casing, at turning on of the fan the krylchatka of the last starts banishing the air given to salon via the heat exchanger, providing its intensive warming up. Activation of the fan is possible only at the included ignition, the choice of the high-speed mode of the fan is provided with the special resistive assembly of a driving electric motor connected to the operating switch.


The heat exchanger by means of rubber hoses is connected to the engine cooling system. Assembly of management of functioning of the heater/conditioner of air is built in in a middle part of the dashboard of the car and by means of change of provisions of the corresponding gates allows to carry out adjustment of temperature and a choice of the direction of distribution of an air stream. The electric motor of the drive of the inlet gate is located in the top part of inlet section of assembly of a heater and, depending on position of the switch of the modes of circulation provides giving in salon of fresh air, or its circulation in volume of salon of the car. The servo-driver of control of regime gates is fixed on the left side of assembly of a heater and on the signals arriving from the operating switches provides the demanded movement of the corresponding gates.

As an additional complete set in a contour of system of heating/ventilation the saloon filter providing purification of the air given to salon of dust can be installed. The filter is located directly behind the fan, ahead of the evaporator module.

1 — the Filtering elements
2 — the K/V Evaporator

The air conditioning system (To/in)

The condenser installed ahead of a radiator, the evaporator, close to the heater heat exchanger fixed on the engine block the compressor, and filtering a receiver dehumidifier (accumulator) equipped with the reducing valve of a high pressure are a part of central air. All components are connected among themselves by refrigerator lines. The coolant circulating in a path of central air leaves the compressor, is banished via the condenser, a receiver dehumidifier and the evaporator, then again comes back to the compressor, a consumption of the coolant coming to the evaporator is regulated by the broad valve which is built in the evaporator.


Temperature of the evaporator is constantly maintained at some set level due to management of activation of the compressor. When temperature of the evaporator falls below a preset value, the special thermosensitive actuation mechanism makes a compressor stop, at temperature increase of the evaporator the same device starts the compressor again.

For protection of a working contour To/in from excessive increase or pressure drop the special sensor switch on which signal blocking of the compressor is also made is provided.

The fan banishes the air coming to salon through the evaporator heat exchanger working in the mode, the return to the mode of functioning of a radiator. The coolant which is pumped over via the heat exchanger begins to boil and, evaporating, selects at air surplus of heat. Temperature in salon thus decreases to the demanded comfortable value (at the choice of the operator). The compressor supports circulation of coolant in system, pumping over the warmed liquid via the condenser where it is cooled and comes back to the evaporator.

Elements of management of functioning of central air are a part of the same assembly with which the choice of working parameters of systems of heating and ventilation is carried out.

Automatic air conditioning system (climate control)

On some models the centralized management of functioning of systems of heating, ventilation and conditioning is organized by air (system of climate control). At such complete set climatic conditions in salon of the car are supported automatically according to the installations entered by the user. Assembly of management of HVAC is located in the central part of the dashboard of the car on a standard place where the control panel of systems of heating/ventilation and conditioning of models of a standard complete set usually is located.

Maintenance of the set temperature is carried out at the expense of the organization in a control system of climate control of feedback with ECM via additional information sensors. The air temperature sensors working by the principle of a thermistor in and outside of the car and the sunlight sensor are among such sensors.


For air supply on a sensitive element of the sensor of air temperature in salon of the car the depression created by an air stream owing to what the sensor functions only at the switched-on heater fan is used.

The sensor of temperature of external air is fixed on a radiator rack behind a decorative lattice of the last that provides good it with in the running stream. For the purpose of increase of thermal power the case of the sensor is made of plastic that reduces speed of response of a thermistor to change of temperature, thus, the sensor fixes only average ambient temperature and is not capable to register its sharp changes.

The basis of a design of the sensor of sunlight is made by the photo diode which is giving out on ECM electric proportional to intensity of sunlight.

On the basis of the analysis of the data of ECM which are continuously arriving from information sensors operates functioning built in a mixing damper by the servomotor by means of draft connected with the damping valve. The potentiometer which is a part of the servomotor informs ECM on the current position of the valve, closing thereby a feedback contour on temperature of the air given to salon.

Similarly the control of damping valves of a choice of the direction of distribution of an air stream, and also the valve of switching of the modes of air circulation is organized.

The basic tension of the powerful transistor of a driving electric motor of the K/V fan changes at the command of ECM that allows to regulate the speed of rotation of a krylchatka in steps. Remark: For protection of a chain against an overload it included the special thermosafety lock working at a temperature of 119 °C and providing a cut-off of power supply from the fan.

Temperature of the evaporator is controlled by the special sensor installed at the assembly exit.


Thus, ECM, based on the analysis of the entering information, is capable to calculate the amount of the air (TAO) forced in salon demanded for maintenance of the temperature condition chosen by the user.

 At input of extreme values of working range (18 and 32 °C) the system is transferred to the fixed condition of the maximum intensity of cooling/heating (on TAO). In the range of values from 18.5 °C to 31.5 °C optimum value of TAO is calculated by the module of management.

Instructions on application

 See also Section of System of heating, ventilation and air conditioning.

Hand-operated models functioning of the air conditioning system

The principle of management of functioning of systems of hand-operated ventilation/heating/air conditioning is illustrated in the table given below. On an illustration schemes of the directions of distribution of air depending on position of the switch are submitted


The percentage ratio of a consumption of air through the corresponding air ducts in various provisions of the operating switch can be estimated on brought on sopr. illustrations to the chart.


Computer-controlled models functioning of the air conditioning system (climate control)

See the Section of System of heating, ventilation and air conditioning.

Precautionary measures

 In order to avoid a scalding, do not uncover a broad tank at all and do not disconnect any components of a cooling path at the hot engine. If there is a need for removal of a cover of a broad tank before full cooling of cooling liquid, (though such situations should be avoided whenever possible), it is necessary to dump previously excessive pressure in system. Wrap up a tank cover a thick layer of rags, then slowly turn off before hissing emergence. When the hissing indicating release of steam stops, slowly turn off a cover up to the end. If at the last stage of an otvorachivaniye hissing is not resumed, can be uncovered. In the course of performance of all procedure do not incline the person over a tank mouth, for protection of hands put on rubber gloves!

Try to avoid hit of antifreeze on open sites of skin and a paint and varnish covering of body panels. Casual splashes should be washed away immediately plentiful amount of clear water. Do not leave the merged from the engine or fresh cooling liquid stored in open container at all. At once collect passage traces rags. Remember that the sweetish smell of antifreeze is capable to draw attention of children and animals. Hit even insignificant amount of cooling liquid in a digestive tract live to an organism is fraught with the most serious consequences, up to a lethal outcome!