What engine Coolant? The function of Anti-freeze Engine Coolant in a vehicle.

Car Engine Coolant

Engine Coolant – When the water freezes in the engine cooling system, the resulting expanding force is often sufficient to crack the cylinder block, pipes, and the radiator. This occurs when the car is parked in unheated areas where the temperature is below freezing point (0°C). To prevent freezing, anti-freeze mixtures or solutions are added in cooling water. The most commonly used anti-freeze materials are as follows:

Anti-freeze Coolant Mixtures

  1. Wood alcohol.
  2. Denatured alcohol.
  3. Glycerine.
  4. Ethylene glycol.
  5. Propylene glycol.
  6. A mixture of alcohol and glycerin.
Anti-freeze Engine Coolant
Anti-freeze Engine Coolant

Alcohol is a volatilé liquid having a lower boiling point than water. Because it evaporates readily, it makes only a temporary anti-freeze mixture. Alcohol mixtures should be checked frequently with a suitable hydrometer to maintain adequate strength. Glycerine has some tendency to attack the rubber hose connection slightly unless the inside of the hose is shellacked. Ethylene glycol is a permanent type of anti-freeze material since it remains liquid at the boiling point of water.

Glycerine and glycol are although costly but do not evaporate readily and hènce prove cheaper in the long run. However, they should be used only in a completely tight system in which there is no leakage into the engine oil. If mixed with engine oil, they cause seizure of the moving parts and result in serious engine damage. They must be used when the cooling system contains a high-temperature thermostat.

permanent type anti-freeze mixtures must be used with air-conditioned cars because, in these, under-the-hood temperatures are higher. The anti-freeze mixtures with lower melting points would soon boil away. The anti-freeze materials are mixed with water in various proportions according to the excepted temperature. The lower the temperature, the higher is the percentage of anti-freeze material.

A good anti-freeze material should have the following requirements:

  1. It should mix readily with water.
  2. It should prevent freezing of the mixture at the lowest temperature encountered.
  3. It should circulate freely in the cooling system.
  4. It should not damage the cooling system by corrosive action.
  5. It should not lose its anti-freezing property after extended use.
  6. It should be reasonably cheap.
  7. It should not waste by vaporization.
  8. It should not deposit any foreign matter in the water jackets or in the radiator.

Propylene Glycol Anti-freeze

The circulation water in the cooling system must be free without any restriction. Usually, the cooling system is clogged by rust and scale formation. The system is completely clogged the water freezės in it. However, the anti-freeze mixtures prevent the freezing of water. Rust and scale formation are the main causes of the cooling system to be clogged.

The impurities in the water determine to a large extent just how much rust and scale will form. Air sucked into the system through the water pump will cause great deal rust. Oil and grease, if mixed into the water due to any means also form scale and corrosion or rust in the system.
The scale formation restricts the passage of water. It prevents the cooling effect also if the radiatór tubes are clogged due to scale formation. It prevents the flow of heat from the water to air.

Anti-freeze Engine Coolant Chart
Anti-freeze Engine Coolant Chart

Anti-freeze For Car

To prevent scale formation, alkali and acid are used. A mild alkali, like washing soda or kerosene, will cut the oil and grease in the cooling system, but will not dissolve the scale formation. The acid will dissolve the scale but will not cut the oil and grease. Besides the use of alkali or acid or a commercially prepared cooling system cleaner, a reverse flush is very effective in all radiators and in some engine blocks.

This reverse flush is made by means of a special nozzle that fits into the lower hose connection and introduces water and compressed air into the radiator. The reverse flow of water under pressure loosens the scales and rust; and forces it out the upper radiator connection, to which a long hose reaching under the engine has been attached. For best results, the radiator and cylinder block should be given a reverse flush separately.

As recommended by some manufacturers, a chemical rust inhibitor is also added into the clean water in the cooling system. It prevents the accumulation of rust.

Understanding all about Anti-freeze Engine Coolant:


Car heater is used to heat fresh air and direct inside the vehicle. In one design, some of the hot water from the cooling system is directed to a small radiator, called a heater core, inside the car. One end of the radiator is connected by a hose to the engine water jacket and the other end to the inlet side of the engine water pump so as to form a separate circulating system.

Electric motor-driven blower fans, air inlets, and air exist to serve to provide fresh air to be heated by the radiator and to be directed inside the car. Other designs of the car heater burn gasoline that comes from the fuel line to provide heat. Some designs contain variable thermostats, called water temperature control valves, in which the hot water feed lines to control the temperature of the heater. The valves are controlled by cables connected between instrument panel units and vacuum-operated mechanism.

Also, Read

  1. How the Radiator Coolant Flush is done? How to Drain Coolant?
  2. How does the engine Water Cooling System work?

One thought on “What engine Coolant? The function of Anti-freeze Engine Coolant in a vehicle.

  • October 6, 2019 at 10:07 am

    Of course, what a great blog and illuminating posts, I will bookmark your blog.All the Best!


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