I present you this guide, thanks to @jackwhoo and 4cardata.

ENGINE COOLANT - CHANGE
- Position the vehicle on a lift.
* Draining instructions.
- Position a suitable container for collecting the engine coolant.
1. Undo the drainage screw in the lower part of the radiator on the left hand side.
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1. Undo the cap for the expansion tank incorporated with the radiator and remove it.

Warning.pngMake sure that the engine is not hot before removing the cap. Danger of burns.
2. Open the bleed screw, incorporated in the expansion tank.
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1. Open the bleed valve on the heater return pipe.
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* Refilling instructions.
- Prepare a suitable quantity of 50% water/Paraflu F02 anti-freeze mixture for refilling the circuit in a container.
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1. Tighten the drainage screw in the lower part of the radiator on the left hand side.
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1. Introduce the refrigerant fluid through the dedicated filler on the expansion tank.
2. Close the bleed screw, incorporated in the expansion tank, as soon as fluid starts coming out.
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1. Continue introducing the refrigerant fluid until it comes out of the bleed screw on the heater return pipe.
- Close the bleed screw.
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- At the end of this operation the refrigerant fluid in the expansion tank will settle down at a level that is considerably higher than the MAX level.

Warning.png For vehicles with air conditioning, make sure that the air conditioning is switched off to prevent the engine cooling fan from coming on when not wanted.
- Close the expansion tank cap.
- Start up the engine and let it idle for about 3 minutes.
- Carry out periodic acceleration up to around 3000 rpm.
- Check that the refrigerant fluid circulation is correctly activated.
- Activate the vehicle interior heater at the maximum temperature and make sure that hot air comes out of the vents.
- When this check has been carried out, switch off the car interior heater.
- Wait until the fan switches on/off for at least 3 cycles.
- Keep the engine speed at about 3000 rpm for 3 minutes.
- Switch off the engine and wait for the fluid to cool down.
- If necessary, top up the fluid until it reaches the MAX level or draw off any excess fluid using a syringe.

Warning.pngThe bleed screws should only be opened if refilling the cooling system with the engine switched off.
Warning.pngAvoid opening the bleed screws at other times under all circumstances to prevent air penetration in the circuit.