Automotive Cooling System Cleaner

Combustion temperatures in automobile engines can exceed 5000.degree. F. About one-third of this heat energy generated by an engine is dissipated by a properly functioning cooling system. If this excess heat is not continuously removed, the engine could sustain costly damage or even burn out.

Because the cooling system does a critical job in keeping the engine at an efficient operating temperature, it is important to properly maintain the system. In its normal job of cooling the engine, however, the cooling system is exposed to corrosion and the accumulation of rust, scale, grease and oil, all of which inhibit the system from operating at peak efficiency. Consequently, a suitable maintenance program should provide for the regular removal of any built-up grease, grime or rust in the system. The present invention relates to a novel composition for removing corrosion, grease and grime in an automotive cooling system.

Compositions that remove corrosion, grease and grime from metal surfaces in general are known. A representative composition is described in U.S. Pat. No. 3,242,093, issued Mar. 22, 1966 to Compton. As pointed out by Compton, most corroded metals that are to be cleaned usually have layers of rust, scale and/or soil composed of oil, grease and dirt on their surfaces. Most known rust removing cleaners, however, cannot be used without precleaning the metal surface to remove the bulk of the undesirable materials prior to removing the rust or corrosion. Furthermore, these precleaning techniques are often complicated, time consuming and quite often require the use of highly toxic chemicals which would not be suitable for domestic or household use.

Consequently, there exists a need for a one-step cleaner capable of simultaneously removing rust, grease and grime, which is also efficient, effective and non-toxic. The present invention meets those needs as they relate to the formulation for an automotive cooling system cleaner.

This novel composition for cleaning automotive cooling systems consists essentially of, by weight, from about:

(1) 30.50-97.55%, preferably 52.02-68.18%, deionized water;

(2) 1-30%, preferably 16-24%, citric acid;

(3) 0.9-27%, preferably 14.5-22%, ammonium hydroxide;

(4) 0.5-10%, preferably 1.2-1.8% of an octylphenoxypolyethoxyethanol, non-ionic surfactant having the formula ##STR1## (5) 0.05-2.50%, preferably 1.2-1.8%, of a non-ionic defoamer comprised of a blend of mineral oils and silica derivatives, having a specific gravity of 0.91-0.93 and a viscosity of 1,000-1,800 centipoise (measured at 25.degree. C. using a #3 spindle at 20 rpm);

the entire composition being adjusted to a pH approximately between 8.5 and 4.5, preferably 5.5 and 6.5.

The invention has been found to be effective in removing grease, grime and surface corrosion from cooling systems formed in whole or in part from one or more of the group of metals consisting of copper, brass, lead solder, cast iron, steel and aluminum.

The most preferred formulation of the invention is a composition consisting essentially of, by weight: 59.81% deionized water, 20.12% citric acid, 18.28% ammonium hydroxide, 1.64% of an octylphenoxypolyethoxyethanol, non-ionic surfactant having the formula ##STR2## and 0.15% of a defoamer comprised of a blend of mineral oils and silica derivatives, having a specific gravity of 0.91-0.93 and a viscosity of 1,000-1,800 centipoise (measured at 25.degree. C. using a #3 spindle at 20 rpm); the entire composition being adjusted to a pH of 6.2.

Directions for use of the invention call for pouring it into a previously flushed cooling system and idling the engine for 30 minutes. The cooling system is then flushed with water and recharged with an appropriate amount of antifreeze and water. For the conditions under which the invention will be used, it has been discovered that the only suitable non-ionic surfactant is an octylphenoxypolyethoxyethanol, non-ionic surfactant, having the formula ##STR3## This product is prepared by reacting 30 moles of ethylene oxide per mole of t-octylphenol. Such a product, suitable for use in the present invention, is marketed by Rohm and Haas as Triton X-305.

Laboratory tests demonstrate that the invention is superior to present cooling system cleaners in the field in its ability to safely clean cooling systems of rust and grease. The test involved immersing in various cooling system cleaners, pre-rusted auto body steel panels and grease coated bronze screens. The amounts of cleaner used, the length of time in the cleaning solution and the temperature of the solution were set according to the product's label directions. Results were as follows:

Of the competitive flush produces suitable for consumer use, it is clear that the present invention is superior. Furthermore, the excellent cleaning properties are obtained without significant risk to the consumer. The invention was tested and classified according to the regulations of the Federal Hazardous Substances Act, the results of which show that the invention is neither an eye or skin irritant nor toxic orally.

The preparation of the invention is straightforward, being a simple "add and stir" formulation involving no unusual process or equipment. The process of preparation is illustrated by the following example.