Empty the cooling circuit.
To clarify the circuit by adding clean water and emptying it again.
Fill the circuit with clean water and add the dose of Pattex Nural 1.
Starting the engine a minimum of 30 minutes, empty and rinse until all the dirt or with the engine stopped, keep the product in the circuit 12 to 24 hours and then empty and rinse until the water clean.
Fill again with water.