Before each coolant drain, add MOTUL RADIATOR CLEAN to the cooling system before exchanging the coolant. Move all heater controls to hot position. Let the engine idle for approx. 30 minutes. Drain the system completely and flush with clean water. Refill the cooling system with new coolant according to the manufacturer's instructions. Attention: Open radiator filling cap slowly and successively - system under pressure - risk of burning! 300 ml is sufficient for cooling systems of 10 L capacity. Do not exceed the recommended proportion. If necessary, proceed to 2 successive treatments.