The coolant must be replaced when the cooling system is repaired, in which the liquid is drained. In the event that the head, block, cylinder head gasket, radiator, heat exchanger or engine are replaced during repair, the coolant must be replaced. During circulation, anti-corrosion additives are deposited on new light metal parts and thus form a durable anti-corrosion layer. The anti-corrosion additive in the used coolant is usually no longer sufficient to form a sufficient protective layer on new parts.
Caution! Drained coolant must not be reused. Coolant is toxic and must not be disposed of with household waste.
Removal
1. Set the interior heater control to the maximum temperature setting.
2. Raise the vehicle and place it horizontally on stands. The operation of lifting and placing the vehicle on stands is associated with danger! Therefore, before carrying out the operation, read Section Jacking and towing Introduction to the manual.
Caution! When the engine is hot, cover the expansion tank with a thick cloth before opening it to prevent burns from hot coolant and steam. The cap should only be removed when the coolant temperature is below +90°C.
3. Open the cap (1) of the expansion tank (2). When the engine is warm, place a thick rag on the cap. Turn the cap slightly to the left and release the pressure in the cooling system. Then unscrew the cap completely.
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4. Place a clean container under the radiator and cylinder block.
5. Open the drain plug (3) on the radiator (4) and allow the coolant to drain into a container.
Note: To ensure that the liquid accurately enters the container, place a hose on the nozzle (5).
The coolant can also be drained from the cylinder block. In this case, place the hose on the drain nipple on the right side of the cylinder block. Open the nipple using the hexagon and drain the liquid into a container. The tightening torque is specified in the Specifications.
6. Drain the liquid completely.
7. Replace the drain plug on the radiator and remove the drain hose.
8. Lower the car onto its wheels.
Filling the system with liquid
1. Prepare new coolant.
2. Fill the liquid through the expansion tank.
Caution: Fill the system with liquid slowly, making sure that no air pockets are formed.
3. Check the coolant level, refer to Section Checking fluid levels, leak monitoring.
Bleeding air from the cooling system
1. Start the engine with the expansion tank cap removed and let the engine idle.
2. Set the heater control in the passenger compartment to the maximum temperature setting.
3. Monitor the fluid level in the expansion tank, topping it up to the MAX mark.
4. Warm up the engine until the coolant temperature reaches 60–70°C or until the upper radiator hose is warm. Then close the expansion tank cap.
5. Let the engine run at 1500-2000 rpm until the radiator fan turns on and then off again.
6. After this, stop the engine.
7. Visually check the cooling system, in particular the hose connections, as well as the drain plug and coolant pump for leaks.
8. Allow the engine to cool down and check the coolant level, top up if necessary.