4.1 Automobile and truck radiators and heater cores are now predominantly made with aluminum alloys using various manufacturing processes including brazing with a flux (See Appendix X1 for additional information). The presence of residual internal brazing flux in heat exchangers along with the high ratio of internal aluminum surface area to coolant volume may affect certain physical and chemical properties and corrosion protection of the coolant. This test method provides a screening test to assess engine coolant physical and chemical properties and corrosion protection after aging it in a heat exchanger brazed with flux at elevated temperature under stagnant conditions. This method cannot stand alone as evidence of satisfactory coolant performance in flux-brazed aluminum heat exchangers. The actual service of an engine coolant formulation can be determined only by more comprehensive bench, dynamometer, and field tests.