1.6.18. Cooling liquid

Cooling liquid provides cooling of the engine. The additive share to cooling liquid is defined by its morostoykost in winter time.
At the plant the cooling system of the engine of the car refuels the cooling liquid intended for long-term work and which is not demanding replacement. Liquid consists of the water and the additive G12+ representing antifreeze on the basis of glycol with anticorrosive additives.

Additive to cooling liquid
The additive share to cooling liquid depends on climatic conditions of operation of the car. At an insufficient share of additive to cooling liquid liquid can freeze. The refusal of a contour of cooling and heating is as a result possible.
As a rule, mix consists of water (60%) and additives (40%). This mix not only provides necessary frost resistance to -25 °C, but also protects from corrosion first of all metal components of the cooling system. Besides, adjournment of a scum is prevented and considerably the liquid boiling point raises.
As additive to cooling liquid use only G12+ or additive according to the TL-VW 774 F specification. Other additives can significantly break its properties and first of all effect of corrosion protection. The resulting corrosion damages can cause leak of cooling liquid and bring in a consequence to serious damages of the engine.
Additive to G12+ cooling liquid can be mixed with other additives (G11 and G12).

Control of level of cooling liquid

Fig. 1.167. Broad tank of the cooling system


Determine visually the level of cooling liquid in a broad tank (fig. 1.167). At the cold engine level has to be between tags of "min" and "max". At the heated-up engine level can slightly exceed a tag
Authentically it is possible to check the level of cooling liquid only at the idle engine.
About falling of level of liquid the control lamp of the display of a combination of devices signals. Despite it, it is recommended to be checked from time to time.

Leak of cooling liquid
Leak of cooling liquid allows to assume, first of all, existence of thinnesses in the cooling system. In this case urgently check the cooling system at the specialized enterprise.
At undisturbed tightness leak can arise only in case of boiling of cooling liquid because of an overheat and its replacement from the cooling system.

ATTENTION
The adulteration of the condensing means of a radiator is not allowed to cooling liquid. Perhaps serious violation of function of the cooling system.

Dolivaniye of cooling liquid
Kill the engine.
Let's the engine cool down.
Cover a stopper of a broad tank of the cooling system with fabric and carefully unscrew it rotation counterclockwise.
Add cooling liquid.
Densely twirl a stopper.
For a dolivaniye use only new cooling liquid.
Liquid is added only to a tag "move". Excess of liquid at its heating is forced out from system via the safety valve in a stopper of a broad tank.
At considerable leak of cooling liquid, it, in order to avoid damage of the engine, it is possible add only after it cools down.

ATTENTION
The cooling system is under pressure. Do not open a stopper of a broad tank of the hot engine – danger of a burn.

NOTE
Do not reuse the merged cooling liquid. It has to be utilized taking into account preservation of the environment.

Cooling system fan
The fan of the cooling system can automatically turn on.
The drive of the fan is carried out through poliklinovy a belt from the engine. The fan is equipped with the viscous coupling regulating the frequency of its rotation depending on temperature.
Besides, depending on version of the engine or a complete set (for example, automatic transmission, the traction coupling device, the conditioner) the additional electrodriving fan automatically turns on. The fan works depending on temperature of cooling liquid and temperature of podkapotny space.
The additional fan can continue to work up to 10 min. and after switching off of the engine and ignition. It can also automatically join in the following cases after a while:
– temperature owing to aerodynamic heating increased or the warmed podkapotny space in addition heats up bright sunshine.

ATTENTION
At work in podkapotny space it is necessary to remember probability of automatic turning on of the fan.

Brake fluid
Level of brake fluid has to be in a tank of the brake drive between tags "MIN" and "MOVE".
Insignificant decrease in level of liquid in process of a run of the car is explained by wear and automatic adjustment of brake slips. This normal phenomenon.

Fig. 1.168. Tank of the brake drive



At considerable decrease in level of liquid for a short period or its falling below a tag of "MIN" depressurization of the brake system is not excluded. About too low level of brake fluid in a tank fire of a control lamp of the brake system signals.

Replacement of brake fluid
Replacement of brake fluid has to be carried out by the expert.
Brake fluid is hygroscopic. Therefore eventually it absorbs moisture from air and accumulates in itself water. The increased content of water a long time can cause corrosion damages of the brake system. Besides, the boiling point considerably goes down and deterioration in brake effect is under certain conditions possible. Therefore replace brake fluid each two years.
Owing to problems of utilization, need of the special tool and special knowledge it is recommended to carry out replacement of brake fluid at the Audi enterprise within inspection service.
Use only of original brake fluid is allowed. The specialized enterprises are informed the brake fluid (DOT 4 specification) which is rather authorized by Audi concern. At the same time brake fluid has to be new.