The coolant must be replaced when the cooling system is overhauled, in which the coolant is drained. If the head, block, cylinder head gasket, radiator, heat exchanger or engine are replaced during the 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.
Attention! Drained coolant must not be reused. The coolant is poisonous 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 dangerous! Therefore, before carrying out the operation, read Section Jacking and towing Introduction to leadership.
Attention! 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 cover should only be removed when the coolant temperature is below +90°C.
3. Open the lid (1) expansion tank (2). With a warm engine, place a thick rag on the cover. Turn the cap slightly to the left and relieve the pressure in the cooling system. Then fully unscrew the cover.
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 suitable container.
Note. To ensure that liquid enters the container accurately, put on the nozzle (5) hose.
Coolant can also be drained from the cylinder block. In this case, put the hose on the drain fitting on the right side of the cylinder block. Open the fitting by the hexagon and drain the liquid into a substituted container. The tightening torque is specified in the Specifications.
6. Completely drain the liquid.
7. Replace the drain plug on the radiator and remove the drain hose.
8. Lower the car on wheels.
Filling the system with liquid
1. Prepare new coolant.
2. Fill in a liquid through a broad tank.
Attention! Fill the system with fluid slowly, taking care not to form air pockets.
3. Check the coolant level, refer to Section Checking fluid levels, leak control.
Removal of 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 to a coolant temperature of 60–70°C or until the upper radiator hose is warm. Then close the cap on the expansion tank.
5. Let the engine run at 1500-2000 rpm so that the radiator fan turns on and off again.
6. Then stop the engine.
7. Visually check the cooling system, in particular the hose connections, as well as the drain plug and the coolant pump for leaks.
8. Let the engine cool and check the coolant level, top up if necessary.