ASTM D1881 Test Method for Foaming Tendencies of Engine Coolants in Glassware
8. Test Solution
8.1 A 33 % by volume solution of reference coolant (Specification D3585 test coolant without antifoam) shall be prepared with the proper quantity of Type II water.
8.2 Prepare a 33 % by volume solution of the coolant to be tested with Type II water. Use the same glassware used to prepare the reference coolant test solution. Rinse the glassware with Type II water between preparations. Additive concentrates shall be diluted with Type II water to recommended use concentration. Preparation of the sample shall be done in accordance with treatment of mixtures described in Test Method D1176. Thus, any insoluble materials will be included in the representative sample.
9. Test Conditions
9.1 Test Temperature - The temperature bath shall be kept at a constant volume (350 to 375 mL mark of the graduated cylinder) throughout the test. The test solution shall be maintained at 88 +/- 1°C (190 +/- 2°F) throughout. This temperature is suitable for both high-boiling and low-boiling coolants.
9.2 Aeration Rate - The aeration rate shall be 1000 +/- 25 mL/min.
9.3 Number of Tests - The reference coolant shall be tested to determine if the glassware and testing equipment is contaminated with residue defoamer. If the reference coolant gives a foam volume of greater than 250 mL and a break time of greater than 8 s, drain the reference coolant from the glassware, rinse with Type II water and use for the preparation of the test coolant.
9.3.1 Each test coolant shall be tested in triplicate, using a freshly prepared test solution (Section 8) for each test. The entire container and aerator tube (see 6.1 and 6.4) shall be cleaned scrupulously between each test. The container shall be cleaned in cleaning bath and the aerator tube shall be immersed first in acetone and flushed back and forth, and then in water and flushed back and forth, using vacuum and air pressure. The entire assembly shall be thoroughly rinsed with Type II water before each test.
NOTE 2 - Scrupulously cleaning of the glassware, aerator tube and diffuser stone between tests will reduce the potential carry-over of antifoam from previous test or glassware detergents that can interfere with test reproducibility.
