Every 38,000 km or every two years.
Do not allow antifreeze to come into contact with your skin or painted vehicle surfaces. In case of contact, rinse immediately with plenty of water. Antifreeze is extremely toxic and deadly if ingested. Do not leave antifreeze in an open container or spilled on the floor; its sweet smell can easily attract children or pets. Check local regulations for the disposal of used antifreeze. In many areas there are special centers for its acceptance.
The cooling system must be regularly drained, flushed and refilled. This procedure is carried out to maintain the quality of the coolant mixture and prevent the formation of corrosion, which reduces the efficiency of the cooling system and can cause engine failure. When servicing the cooling system, the condition of all hoses and radiator cap should also be checked and, if necessary, defective components should be replaced.
Dehumidification
1. If the vehicle has just returned from a trip, wait several hours for the engine to cool completely before starting the procedure.
2. After the engine has cooled down, remove the expansion tank or radiator cap. If the cover must be opened when the engine is not completely cool, do so slowly and with care to avoid burns.
3. Place a large container under the radiator to collect the coolant. Where there is a drain plug, unscrew it (depending on the model, you may need a pair of pliers or a screwdriver to do this). Where there is no drain plug, you will have to disconnect the bottom hose from the radiator.
4. While the coolant is pouring out, check the condition of the radiator hoses, heater and clamps (see section if necessary Fuel system check).
5. Replace defective hoses and clamps (see chapter Cooling system, for a detailed description of the replacement procedure).
Flushing
1. After the system is completely drained, flush the radiator with clean water from a garden hose until clean water comes out of the drain or bottom hose. If the radiator is severely rusted, damaged, or leaking, it should be removed (see chapter Cooling system) and send it to a repair shop for a radiator specialist.
2. The flushing described above will remove various deposits from the radiator, but will not be able to remove rust and scale from the surfaces of the engine and cooling pipe. All this can be removed with a chemical cleaner. Follow the purifier manufacturer's instructions for this procedure. Before flushing the engine, open the drain plug of the cylinder block.
3. On suitably equipped models, remove the overflow hose from the expansion tank. Drain the tank, rinse it with clean water and connect the hose.
Filling
Tighten the radiator drain plug or connect the lower radiator hose. Install and tighten the cylinder block drain plug.
Four-cylinder engines
1. Slowly pour new coolant into the radiator (40%/60% antifreeze/water mixture) before it is filled. Pour the coolant into the expansion tank to the bottom mark.
2. Without closing the radiator cap, in a well-ventilated area, start the engine and run it until the thermostat opens (coolant will flow through the radiator and the upper radiator hose will heat up).
3. Turn off the engine and let it cool down. Add coolant to the radiator up to the base of the filler neck. On M40 engines, unscrew the air bleed valve at the top of the radiator and add coolant until coolant flows out through the bleed hole. Install and tighten the valve.
4. Squeeze the upper radiator hose to remove air, then add coolant again if necessary. Close the radiator cap.
5. Start the engine, warm it up to normal operating temperature and check for coolant leaks.
Six-cylinder engines
1. Loosen the air release valve in the thermostat housing.
2. Pour a 40%/60% antifreeze/water mixture into the radiator until it starts to overflow into the air outlet valve. Tighten the valve.
3. Close the radiator cap and start the engine; run it until the thermostat opens (upper radiator hose gets hot). Slowly loosen the air release valve until no more air bubbles come out, then tighten the valve.
4. Repeat the procedure until the air is removed from the system.