Attention! The expansion tank plug shown in Fig. 135, open only when the coolant temperature does not exceed 90°C. The recommended temperature is -50°C. Turn the plug one turn, wait until the pressure equalizes, and remove it completely. Place a thick cloth over the plug when opening to avoid burns from steam or splashes of hot coolant.
Plain water can be used to make up for small losses of coolant. Lime-free, rainwater, distilled water is not suitable for the cooling system as it can cause corrosion.
If during the trip the liquid level in the cooling system has significantly decreased, cold water must not be poured into a hot engine, since the block head may be deformed. A small amount of water can also be added to a warm engine. Coolant replacement is carried out in the following order:
- if the engine is hot, to top up the coolant, slowly unscrew the plug to release the steam. The coolant temperature must never exceed 90°C. When opening, first turn the plug one turn, wait until the pressure equalizes, and only then open further;
- unscrew the fasteners and remove the radiator protection under the engine;
- Drain the coolant from the underside of the radiator into a container underneath. If the antifreeze intended for further use is drained, use an appropriate container;
- To prevent the formation of air pockets when filling the system, the following simple recommendations should be considered:
- 1) regardless of whether the car has air conditioning or not, set both heater controls to maximum heating, with automatic climate control installed, press the DEF button;
- 2) pre-prepared antifreeze (see subsection 4.1.2) pour into the radiator until its level reaches the lower edge of the filler neck. For the convenience of determining the level, you can use «carrying». Do not tighten the filler plug yet;
- 3) start the engine and warm it up to operating temperature, i.e. before the thermostat opens. Wrap the filler plug when the temperature reaches 60–70°С;
- check coolant level.