Who Needs Anti-Freeze in the Tropics?

Many years ago when starting out as an instructor in Saudi Arabia, I ended a class by pushing the trainees to ask questions. With no takers, in desperation I finally said, “Ok, if you’ve no questions, we’ll have the test now.” Suddenly a hand shot up and I had a question...

“Sir Tom, why do I have to put anti-freeze in my car, it’s hot here?” Oops, I had forgotten to say ‘questions on the topic’ of my lecture — basic radar systems. I stumbled through some broad reasons but later went out of my way to learn why anti-freeze is needed in countries where the temperature never falls to anything near freezing. This proved worthwhile as a surprisingly large number of people have since asked me the same question.

Why do you need anti-freeze in the tropics?

So, have you ever wondered why your car needs antifreeze even if you live in the tropics or elsewhere that temperature never falls below freezing?

Simple answer is that you don’t so much need the anti-freeze itself, but the additional additives it contains. No matter where you live, your engine needs the corrosion inhibitors contained in anti-freeze. Without them, especially if you have an older iron block, rust quickly forms. Not only does the rust reduce the effectiveness of your cooling system – and an overheated engine is no fun – eventually the fine rust particles block off parts of the system. This is one of the reasons why so many older cars in the Philippines don’t have working heaters. It’s a combination of using just water for coolant, and using the cars heater so rarely; the heater radiator literally becomes clogged with rust particles.

Another reason anti-freeze is useful is that in many cases, the coolant fluid has much better heat transfer properties than water. This means that the coolant both absorbs heat quicker (taking  heat away from the engine), and it releases heat quicker, cooling more effectively as it passes through the radiator.

Of course, not all anti-freeze contains the same inhibitors and additives. Car manufactures' spend large amounts developing coolants whose chemical mix is just right for the materials in their  engines.

This means that there are many different types of anti-freeze and coolants – and you must make sure you use the right one for your vehicle. I well remember a friend who had a lively little Hillman Imp, or at least it was until he tried to save some cash by mixing up some left over anti-freeze he found in his dad’s garage – and just about dissolved the Imp’s aluminum alloy engine as a result.

Happily, advances in technology mean that modern anti-freeze is not as harsh and unforgiving as it once was (remember those splashes that discolored the paint!). But, even though anti-freeze is much more forgiving, you should still check that the coolant you use meets your engine’s needs – and never ever mix different types of antifreeze in the same system – the results can be disastrous.