Abstract: A test substrate for determining concentration of an organic corrosion inhibitor in a coolant fluid is provided. The test substrate comprises a porous substrate having at least a surface treated with a sufficient amount of at least a metal salt for reacting with a molar equivalent amount of the organic corrosion inhibitor in a representative sample of the coolant fluid, and at least a color indicator. The color indicator reacts with the metal salt and/or the organic corrosion inhibitor, forming an irreversibly colored complex and causing a color change in the test substrate.

Abstract: The invention includes, in one embodiment, a method for determining the presence or absence of a corrosion-inhibitory level of carboxylate anion in used engine coolant which includes: obtaining a known quantity of the engine coolant as a representative sample thereof, the sample containing a level of carboxylate anion to be determined; adding a fixed quantity of an aluminum containing color indicator to the sample, where the color of the aluminum color indicator is different from the original color of the sample, thereby changing the color of the sample to substantially the color of the aluminum color indicator, where at least a portion of the aluminum color indicator complexes with at least a portion of the carboxylate anion to form a colored insoluble aluminum-carboxylate complex, where the colored insoluble aluminum-carboxylate complex precipitates, and where the color of the sample remains substantially the color of the aluminum color indicator when the level of carboxylate anion therein is below an effec

Abstract: A colorimetric method is provided for determining the presence or absence of a corrosion-inhibitory level of carboxylate anion in used aqueous engine coolant.

Abstract: A calorimetric method is provided for determining the presence or absence of a corrosion-inhibitory level of carboxylate anion in used aqueous engine coolant.

Abstract: An improvement is provided in a process for making a calcium sulfonate wherein a calcium base/calcium sulfonate mixture is mixed, stirred, reacted with CO.sub.2, and filtered to produce the sulfonate product. The improvement comprises stirring the calcium base/calcium sulfonate mixture at variable speeds over a sufficient length of time, whereby the product's filterability is enhanced and viscosity reduced.

Abstract: A method of preparing a amorphous metal sulfonate detergent for lubricants. The sulfonate detergent is prepared by:(a) mixing, stirring and heating a diluted metal sulfonate with Ca(OH).sub.2 ;(b) adding to the stirred, heated sulfonate mixture a sufficient amount of CO.sub.2 to heat with all the Ca(OH).sub.2 added;(c) adding a zeolite to the mixture partway through the addition of CO.sub.2 to remove a certain percentage of the total water in said mixture;(d) filtering the water-removed mixture to separate an amorphous metal sulfonate product; and(e) recovering the amorphous overbased metal sulfonate product.