ASTM D3634 Trace Chloride Ion in Engine Coolants
Many engine coolants contain chlorinated compounds. The presence of residual chloride ions may accelerate corrosion in the coolant system. This test determines low levels of chloride ions in coolants that also contain mercaptans – a common additive used to inhibit corrosion.
The sample is placed in an Erlenmeyer flask and diluted with water. Sodium hydroxide and hydrogen peroxide are added, the mixture is refluxed, acetic acid is added and the mixture is titrated with silver nitrate. The ppm of chloride in the coolant is reported.