Antifreeze-What Does It Do ? – Why Do You Need It ?

Antifreeze-What does it do-Why you need it.

Make sure that you have the correct antifreeze in the right concentration. This is critical to the health of your engine.

  • Also the coolant capacity of modern systems is smaller.
  • Also operating temperatures and pressures are higher.
  • The use of lightweight materials such as aluminum increase the risk of corrosion.
  • In addition several different metals are now used to manufacture engines.
  • As a result this makes it harder to prevent corrosion and scale build up in the cooling system.
  • Furthermore cooling system problems are responsible for  about 60% of engine failures.

Antifreeze has many functions and is vital to the correct operation of the engine.

clean engine coolant
clean engine coolant

Coolant/antifreeze needs to have the following features:

  • Corrosion prevention
  • Excellent heat transfer
  • Protection from freezing
  • Prevention of scale build up
  • Compatibility with hard water
  • Stability at high temperature
  • Compatibility with plastics and elastomers used in the engine
  • Low foaming

Propylene glycol is a less hazardous alternative to ethylene glycol. In addition it is much more expensive and some manufacturers have been reluctant to use it.

Recent technical advances have been in the field of corrosion prevention and control of scale build up. Engine design has changed to improve fuel efficiency and lower emissions as well as reducing weight and costs. These demands have made engine operating conditions even more severe.  Vehicle manufacturers choose the antifreeze they use at the factory.

contaminated engine coolant
contaminated engine coolant


Beyond the warranty period, it is still best to follow the vehicle manufacturer’s recommendation. However the coolant/antifreeze used should at least meet minimum specifications.

If you have to add coolant there is a problem. As a result the coolant level the radiator expansion tank drops, confirming a leak.

There are many older vehicles which still use traditional antifreeze. These coolants are cheaper than the longer life technologies and, do not achieve the same corrosion protection.

Water quality

There is still one factor that can reduce their effectiveness, the quality of the water used for dilution!

High levels of calcium and magnesium in tap water, can also lead to deposits and scale build up. It is advisable to use distilled water in the cooling system rather than tap water.

Frequently Asked Questions (FAQs)

What is the difference between coolant and antifreeze?

Antifreeze is a concentrated product and has to be diluted for use. The diluted liquid is usually called coolant.

How do I find out what type of coolant should be in my car?

Ask your dealer or check your owner manual.


How do I find out what type of coolant is in my car?

The color of the coolant does not prove type or quality of the product. The best course of action is to drain and flush the system and refill it with the recommended type of coolant.

Who uses propylene glycol?

Propylene glycol (PG) based antifreeze/coolant is offered by a number of suppliers as a less toxic alternative to ethylene glycol based products. Good quality PG products have a very similar performance to ethylene glycol based products. They are used by people who are worried about the toxicity of ethylene glycol based products.

poor water
poor water

Which types of coolant can form sludge when mixed?

Good quality coolants should not form sludge. Poorer quality coolants and/or the use of excessively hard water can form sludge.  Mixing different types of coolant will also reduce the corrosion inhibitors effectiveness.

I want to replace /top-up the coolant, what should I use?

For replacing or topping-up, you should use the product recommended by the vehicle manufacturer. This should be one that meets the specification indicated by the vehicle manufacturer. It is important to ensure that this is diluted to the correct mix with good quality water.

The antifreeze I use is too expensive – can I use something cheaper?

For most people a car is a significant investment. In comparison the price of even the most expensive antifreeze is relatively minor. Purchasing a good quality antifreeze will help to protect that investment.

You should use only the vehicle manufacturers recommended fluids while the vehicle is in warranty. When out of warranty, use an antifreeze/coolant meeting the same specification and renew at the recommended times.


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