2.4. Engine cooling system

The cooling system of the engine is filled at manufacturer with cooling liquid of long action which should not be replaced.
Cooling liquid consists of 60% of water and 40% of a low-temperature concentrate of G12 A8D (low-temperature structure on the basis of ethylene glycol with anticorrosive additives). This mix not only provides operability of the cooling system of the engine up to the temperature of -25 °C, but also protects from corrosion of a detail, especially from light alloys. Besides, it prevents scaling and significantly increases temperature of boiling of cooling liquid.
Therefore contents low-rate-raturnogo of a concentrate in warm season and in the countries with warm climate it is impossible to reduce dolivky water. The share of a low-temperature concentrate in solution has to be not less than 40%.
In the conditions of severe climate it is possible to increase the maintenance of a concentrate of G12 A8D, but no more than 60% (temperature of freezing of cooling liquid in this case will make about -40 °C) as at bigger percentage of a low-temperature concentrate temperature of freezing will begin to increase and indicators of a thermal capacity and heat conductivity of cooling liquid will worsen.
As a low-temperature concentrate it is necessary to use only structure of G12 A8D or a concentrate with the TL-VW 774 D specification (pay attention to an inscription on a container).
Other concentrates can be more aggressive first of all in relation to anticorrosive coverings.
The corrosion of metal details which arose owing to influence of a concentrate can lead to leak of cooling liquid that in turn will cause serious damages of the engine.
At a dolivka of cooling liquid it is impossible to mix structure of G12 with other low-temperature concentrates at all (and with structure of G11).
The structure of G12 can be determined by red color of cooling liquid in a broad tank. If cooling liquid in a broad tank of brown color, so the structure of G12 is mixed with other low-temperature concentrate! In this case it is necessary to replace surely cooling liquid as it can become the reason of serious violations in operation of the engine.

Check of level and density of cooling liquid
The broad tank of the cooling system of the engine is located in a motor compartment.
Level of cooling liquid should be checked only on the idle engine.

Fig. 2-9. Check of level of cooling liquid in a broad tank

On the cold engine it has to be between the marks MIN and MAX of a broad tank, on the heated-up engine – the marks MAX are slightly higher (see fig. 2-9).
For check of density it is necessary to use the areometer.
Considerable decrease in level of cooling liquid most likely testifies about violation of tightness of consolidations. In this case it is necessary to address to the service enterprise Volkswagen immediately.
In the tight cooling system the level of cooling liquid can decrease at an engine overheat when cooling liquid boils and is thrown out outside.

Dolivka of cooling liquid
Stop the engine and let's it cool down. Cover with a rag a stopper of a broad tank and carefully turn out it counterclockwise.
If in the circumstances you have no low-temperature concentrate of G12 A8D, it is not necessary to add other concentrate to system. In this case it is possible to add water and as soon as possible it is obligatory to restore necessary composition of cooling liquid addition of the recommended low-temperature concentrate.
At big loss of cooling liquid the dolivka should be carried out only on the cooled-down engine to avoid its breakage.
Do not pour cooling liquid above the mark MAX: excessive liquid owing to its expansion will follow from the cooling system via the safety valve located in a stopper.
Reliably screw up a stopper of a broad tank.