The vehicle coolant system has the power to ruin you whole car if it fails. It has to be watched via instruments on the dashboard and the cars performance. 

There are many reasons why your car maybe overheating and all of them should be addresses as soon as possible if you wish to keep your vehicle running as it was meant to be. Sometimes over heating problems can be fixed on modern cars with nothing more than a laptop computer.bIn this section we will go through the possible causes and solutions that you can try.

Ironically older engines were a lot better at tolerating engine overeating. The engines used to be made from steel and this easily handled the extreme temperature changes, although the performance and efficiency was less from steel. Most modern engines are made from aluminum which are much less robust when dealing with extreme heat.

Engines are cooled by engine coolant which consists of mostly water added to anti freeze being pumped around the engine block. Anti freeze also works to protect the water from boiling away by raising the boiling point of the water and thus protects the car from being too hot as well as being too cool.

Engine coolant is pumped around the car by a water pump connected in most cases by a belt to the engine. Cool engine coolant is pumped around the engine chambers where it cools the internal workings of the engine and in turn the coolant is heated. The warm coolant is then pumped away from the engine to the radiator where it is cooled by cold air hitting the front of the vehicle whilst the car is in motion. Once the coolant has been cooled by the radiator, it then is pumped back to the engine to begin the cycle all over again.

So very basically all the engine coolant system is, is a big circle of pipes with the engine at one end heating the fluid, at the other a radiator to cool it.

Here we go through some of the most common issues with regards the over heating of the engine and some simple tips on possible fixes. Please remember that the coolant fluid is very hot after the vehicle has just stopped and may be so for many hours afterwards. So please do not attempt any repairs or investigative work until you are very sure that the fluid is cool, this can takes anything up to 4-5 hours on warm days.

1) Air trapped in the system, any air that is trapped in the coolant fluid will do things a) hamper the water pump from pumping fluid around the system b) minimize the cooling affect of the coolant fluid once it gets to the engine. Most coolant systems should have a "bleed key" somewhere near the radiator. The bleed key will allow air to escape from the system.

Warning the bleed key should be opened whilst the system is under pressure to force the air out. This means it will be hot and dangerous, so this should only be done by a trained mechanic or someone is truly confident of the process.

If your system does have air trapped inside it, the dial should fluctuate with the dial reading high temperatures and then low temperatures in a short space of time. One consequence of air being trapped in the system is that it may prevent the fan behind the radiator being activated by the thermostat. This will mean that the radiator is unable to cool the coolant when the vehicle is not in motion.

2) Head Gasket Failure, this is one of the most serious problems it could be. It usually means removing the head of the engine and replacing the gasket (thin paper like seal).

Symptoms of head gasket failures are a) rises in temperature of the vehicle b) Coolant that is discoloured and has been contaminated by engine oil, plus the strong smell of oil.

Head Gasket failures are caused by the breech of the gasket seal around the cylinder head. This then allows the coolant fluid to mix with engine oil and hot combustion gases which should be travelling down the exhaust, not back into the engine block. Eventually the failure will lead to the engine overheating and warping the head unit of the engine.

The only solution to a head gasket failure is to have the gasket replaced, plus you may need to clean the oil and coolant pathways before replacing the gasket. This is because the become blocked when oil and coolant mixes with a orange coloured substance.