Coolant, engine

Enflurane [13838-16-9]C Engel-Precht process Engine coolants... 

The freezing point of the coolant should be monitored for coolants in all types of service. Additionally, maintenance of the corrosion inhibitor levels is requited of the heavy-duty service coolants and the stationary engine coolants. Because corrosion inhibitors and combinations of corrosion inhibitors work most effectively at given concentrations and specific ratios to the other inhibitors, appropriate concentrations must be maintained to maximize corrosion protection. Many manufacturers of coolants for stationary engines, and manufacturers of SCAs, provide an analytical service to monitor the effective inhibitor concentrations in the system periodically. Recommendations can then be made for proper maintenance and inhibitor replenishment. 

Human toxicity, aquatic toxicity, and the environmental impact of engine coolants and deicing fluids ate typically measured on the fresh fluid only. Spent fluids contain varied contaminants that can drastically affect the toxicity and environmental impact of the fluid. Most pronounced is the impact of heavy-metal contaminants in spent antifreeze. Data on spent and recycled antifreeze, compiled by the ASTM Committee on Engine Coolants, show an average lead level 11 ppm, as weU as various other metal contaminants (iron, copper, zinc) (18). The presence of these contaminants in a used fluid may require special disposal techniques for the fluids. 

Because of the problems with some recycling options, the ASTM committee on engine coolants is exploring a specification for recycled coolants. 

Some automobile manufactuieis have found the in-shop recycling equipment to be ill-advised one service bulletin warns of the deterioration of engine-coolant ethylene glycol to the extent that no additive can restore it to an acceptable state (21). 

General Motors Engineering Standards. Automotive Engine Coolant, Antifreeze Concentrate-Ethylene Glycol Type, GM 6038-M, Jan. 1971 Automotive Engine Coolant, Concentrate-Ethylene Glycol Type, GM 6043-M, Sept. 1983. 

Worldwide Trends in Engine Coolants, Cooling System Materials, and Testing SP-811, Society of Automotive Engineers, Warrendale, Pa., 1990. 

ASTM Committee D-15 on Engine Coolants (Minutes), Memphis, Term., American Society of Testing and Materials, Philadelphia, Pa., 1990. 

The excellent chemical resistance of Aflas has led to important applications in oilfields and, more recently, in the car industry in place of FKM rubbers because of the better resistance to new types of engine oils, transmission fluids, gear lubricants and engine coolants. 

Dissolved solid and gaseous impurities can also affect the pH of the system and this may often lead to decreased inhibitor efficiency. In industrial plant, cooling waters can take up SOj, HjS or ammonia and pH control of inhibited waters will be necessary. The leakage of exhaust gases into engine coolants is an example in which corrosion can occur despite the presence of inhibitors. 

In the UK, a standard for describing minimum requirements for inhibited engine coolants is provided by BS 6580 . (Test methods are described in BS 5117.)... 

There has been much activity in this field of corrosion inhibition in recent years which appears to have been prompted by health and safety requirements. As with engine coolants, the use of nitrites, particularly where amines may also be present, needs to be considered carefully. Nitrites have been widely used in cutting, grinding, penetrating, drawing and hydraulic oils. Suggested replacements for nitrites and/or amines make use, inter alia, of various borate compounds, e.g. monoalkanolamide borates. Molybdates have also been proposed in conjunction with other inhibitors, e.g. carbox-ylates, phosphates, etc . Water-based metalworking fluids usually contain other additives in addition to corrosion inhibitors, e.g. for hard-water stability, anti-foam, bactericidal proderties and so on. Thus, claims are made for oil-in-water emulsions with bactericidal and anti-corrosion properties. 

Inhibitor concentrations should be checked on a regular basis and losses restored either by appropriate additions of inhibitor, or by complete replacement of the whole fluid-as recommended, for example, with engine coolants. 

Examples of various vibratory test procedures for studying cavitation-erosion of metals in inhibited engine coolants have been given in an ASTM Special Technical Publication... 

The three types of test procedure discussed in this chapter may often be identified in testing of inhibitors or inhibited products. The testing of inhibited engine coolants provides a suitable example. 

Mercer, A. D., Laboratory Research in the Development and Testing of Inhibited Coolants in Boiling Heat Transfer Conditions , in Engine Coolant Testing Slate of the Art 1979. ASTM STP 705, W. H. Ailor, ed., 53-80 (1980)... 

Testing corrosion inhibiting, engine coolant concentrate ( antifreeze )... 

D 1384 1987 Method for corrosion test for engine coolants in glassware... 

D 2570 1985 Method for simulated service corrosion testing of engine coolants... 

D 2758 1986 Method of testing engine coolants by engine dynamometer... 

D 2809 1989 Test method for cavitation erosion-corrosion characteristics of aluminium pumps with engine coolants... 

D 2847 1985 Practice for testing engine coolants in car and light truck service... 

Test method for corrosion of cast aluminium alloys in engine coolants under heat-transfer conditions... 

Antifreeze is designed to prevent engine coolant from freezing at the low temperatures encountered in winter and at high altitudes. These temperatures often fall several degrees below freezing, so the value calculated in this example is what we would expect for antifreeze. 

R. Hohlfeld. Longer life for glyco-based stationary engine coolants. Pipeline Gas J, 223(7) 55-57, July 1996. 

These grades have been developed to give improved chemical resistance to automotive fluids such as gear lubricants, transmission and power steering fluids, engine oils, and rust inhibited engine coolants. Resistance to aromatic hydrocarbons is reduced. 

Performance is also a consideration and in some instances favors polymers over steel. DuPont developed a nylon water jacket spacer for the 2006 Toyota Crown and Lexus GS-300. It did not reduce weight, but did increase the heat-transfer efficiency between the engine coolant system and the cylinders lowering the fuel consumption by 1% or an equivalence of over 50 lb. 

Manual on Selection and Use of Engine Coolants and Cooling System Chemicals ... 

Manual on selection and use of engine coolants and cooling system chemicals/Ioseph A. Lima and George R. Otterman, editors.—4th ed. 

This ASTM manual has been developed by Committee D-15 on Engine Coolants and is a revision to ASTM Special Technical Publication (STP) 120B. This publication provides consumers with practical information and advice on engine coolants as well as cooling system chemicals, such as cleaning compounds and practices, antirusts, and stop-leaks. This fourth edition presents new information on coolants containing silicates for the protection of aluminum components in today s engines. 

The procedures and practices described herein have no official status as ASTM standards. However, Committee D-15 has developed full consensus standards, and some of these standards are specifically cited in this manual. The full set of the Committee D-15 standards on engine coolants are published in Volume 15.05 of the Annual Book of ASTM Standards. 

Corrosion is effectively controlled by using chemical inhibitor systems which are added to the glycol to make a complete coolant concentrate formulation commonly referred to as permanent engine coolant. 

Follow the recommendations of your vehicle manufacturer concerning engine coolants and be certain the product you select conforms to standard specifications for engine coolant such as ASTM Specification for Ethylene Glycol Base Engine Coolant (D 3306). Any high quality engine coolant must pass the requirements of this specification. 

---