The total apparent water in engine coolant concentrate as determined by Karl Fischer titrations consists of the fol-
lowing: (1) water present in the original glycol base; (2) water added (for example, inhibitor solutions); (3) water of hydration of inhibitors (for example, Na ₂B₄O₇·5H₂O); ( 4) water formed in the chemical reaction between borate and ethylene glycol, producing boratediol condensate and water; and ( 5) quantitative interference by the reaction of the reagent with inhibitors such as tetraborate or sodium hydroxide.

1. Scope

1.1 These test methods cover the determination of the water present in new or unused glycol-based coolant concentrates using a manual (Test Method A) or an automatic (Test Method B) coulometric titrator procedure.

1.2 Many carbonyl compounds react slowly with the Fischer reagent, causing a fading end point and leading to high results. A modified Fischer reagent procedure is included that minimizes these undesirable and interfering reactions.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazards statements see Sections 8 and 16.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D156 Test Method for Saybolt Color of Petroleum Products (Saybolt Chromometer Method)

D1176 Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes

D1193 Specification for Reagent Water

E203 Test Method for Water Using Volumetric Karl Fischer Titration

Keywords

engine coolants; Karl Fischer; water content; Engine coolants/concentrates; Iodine reduction; Karl Fischer reagent method--water content; Water content--chemicals

ICS Code

Citing ASTM Standards

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