Saab:: 9-5: Engine cooling system

5.1. Engine cooling system

Scheme of the cooling system of 4-cylinder engines


1 — the Radiator 2 — the Broad tank 3 — the Water pump 4 — the Engine 5 — the thermostat Case 6 — the heater Heat exchanger	7 — the throttle Case 8 — the Turbocompressor 9 — the ATF Oil cooler 10 — OZh temperature Sensor 11 — the cut-off Valve 12 — the radiator Fan

Scheme of the cooling system of petrol V6 engines


1 — the Water pump 2 — the Engine 3 — the Thermostat 4 — the Radiator 5 — the heater Heat exchanger 6 — the Broad tank	7 — the Electric pump 8 — the Oil cooler 9 — the throttle Case 10 — the cut-off Valve 11 — the Turbocompressor 12 — the radiator Fan

Scheme of the cooling system of diesel V6 engines


1 — the Water pump 2 — the Radiator 3 — the thermostat Case 4 — the Oil cooler 5 — the EGR Valve 6 — EGR cooling Tube	7 — the Turbocompressor 8 — the Additional heater 9 — the heater Heat exchanger 10 — the Circulation pulser 11 — the Valve 12 — the Broad tank

The cooling system of the engine works on the following algorithm. Until the engine is heated-up, the cooling liquid (CL) is pumped over by constantly working pump only in a head and the block of cylinders, and also in the heat exchanger of a heater of salon. At temperature increase of OZh to a certain level the thermostat opens a big contour of cooling and OZh circulates in addition through a radiator (from top to down) and is cooled with the air passing through it. At achievement of temperature of OZh of higher value the electric fan of the cooling system which creates an additional air stream through radiator edges for more intensive heat removal from it turns on. In process of opening of the thermostat the liquid volume given from it to the heater heat exchanger decreases. On models with petrol V6 engines the broad tank is connected to the throttle case for ensuring its heating.

The water pump is given from a bent shaft: on petrol models a belt, and on diesel – directly through a gear wheel. The thermostat of 4-cylinder engines is in the case located on the left side of the engine. The thermostat of petrol V6 engines is located on the right side of the engine. On diesel models the thermostat is placed in the case, fixed on the oil cooler (in front of the engine), and equipped with the additional valve for pumping of the cooling system. On 4-cylinder models without conditioner of air (K/V) one fan of a radiator operated by signals from the sensor of temperature of OZh (ECT) is installed. On other models two fans of a radiator are installed. Fans of models with To/in turn on in the following cases:

At achievement by temperature of OZh of a certain value (see Specifications);
At turning on of the K/V compressor (at a low speed) if ambient temperature is higher the 22nd hail., or at the movement of the car with a speed below 38 km/h and pressure in the K/V lines between 9 and 18 atm.;
At turning on of the K/V compressor (at a high speed) if pressure in the K/V lines is higher than 18 atm.

Before work in a motive compartment, especially in the field of the radiator fan, surely disconnect a negative wire from the rechargeable battery and the fan electrical wiring socket. The fan of a radiator can turn on because of effect of heat conductivity even at the switched-off ignition.

Do not open a cover of a broad tank of OZh before full cooling of the engine in order to avoid a burn hot liquid or its steam.

If necessary to open a cover of a broad tank at the hot engine wind it with a thick layer of rags. Uncover slowly, gradually reducing vapor pressure.