Explaining the cooling system of your engine

Esther Adong was driving back home from work in the evening when she saw smoke coming out of her bonnet. She parked aside and called her mechanic to come and sort out the issue.
She was told she needed to replace her radiator. This was the second time she was doing that in a year.
Besides Adong, it is a common occurrence to find cars stuck in the middle of the road with an open bonnet. When you observe, you realise that there is water under the car or smoke coming out of the car meaning the engine has overheated and that is why the radiator is producing smoke.

What is a radiator?

Radiators play a very vital role in the running of the car and maintaining the engine. Richard Okiror of Richoki Motor garage in Namuwongo says the radiator works like the circulation system of the body.
“Radiators are partly used for cooling the engine,” he says. A radiator has fins where water passes through a thin layer lined up vertically. The water is cooled through a fan before it goes back to the engine.
Okiror explains the cause of the heat, saying it comes as a result of the internal combustion engines which generates friction.
“Even with the use of the motor oils which reduce the friction by making everything slippery to allow the internal components to move with minimum amount of resistance, the engine still produces a vast amount of friction,” he says. He adds that the friction creates heat, which is very bad for the car engine. This is where the car cooling system plays a pivotal role in getting rid of the heat as quickly and efficiently as possible.

How it works

The car cooling system is a combination of several features such as a radiator, fan, water pump, thermostat, a sensor or two, an overflow tank, water, coolant, and a series of belts, clamps and hoses to connect it all together and make it function.
“The system works by directing fluid past the hottest parts of your engine (the cylinder heads and valves), then redirecting that fluid out to the radiator, where the water is cooled before it flows back to the engine.” Okiror elaborates.
A coolant is usually topped in the radiator and it is this fluid that flows through the cooling system.
Augustine Kasobya, a mechanic with JK Auto Garage, explains that the coolant, which is usually blue, green or red in colour, contains both water and a coolant.
It contains a chemical which helps extend the freezing point of the boiling water making it good for use in car radiators.
According to Edmunds, a car website, the fluid in the car’s cooling system contains ethylene glycol. This is responsible for the cooling of the fluid.
The coolant is also said to inhibit rust which is good for the engine.
Kasobya says the coolant is driven through the car system by a water pump which is usually driven by the engine pulley. The system also includes a thermostat, which senses temperature and controls fluid flow within the system, a plastic overflow tank, which serves as a reservoir for excess coolant generated due to the expansion of the fluid due to heating.

Composition of a radiator

Richard Okiror of Richoki Motor Garage explains that the radiator is made of aluminum or rubber caps and they are located on the front grille of the car. It has tubes like the radiator core which contains the coolant. Attached to the tubes are metals which are called fins.
These fins increase the surface area of the radiator, exposing the heated fluid within to the cooler surrounding air thereby cooling the liquid.
The radiator has a fan inside, which is driven by the engine belt. Whenever the car is switched on, the engine belt moves there by moving the fan as well. However, in new cars, the fan is electric and runs only when you need it. The temperature gauge is able to detect temperature changes. This is done by the thermostat, which senses temperature and controls fluid flow within the system.

Caution

Make sure you have enough coolant. Make sure your radiator is full of coolant because if your coolant or any fluid is extremely low, you may also have a leak.
Make sure your coolant is fresh.Like a lot of the fluids that help your vehicle’s components operate, coolant has a lifespan. After that time, it will leave deposits in your engine and radiator that can lead to poor coolant flow.
Check your drive belt. Your drive belt drives everything, including the water pump for your alternator. If the drive belt breaks, there’s no water pump, no coolant circulation, and your engine will overheat almost immediately.
Clear your radiator. Always check your radiator for rubbish because this can block the airflow through your cooling system and cause big problems.
Inspect your radiator cap. A weak radiator cap is a potential culprit you might consider. Your radiator cap needs to be in good shape and properly fastened.

Common causes of radiator problems
Excess heating in a car is caused by a leakage in the radiator. Like Adong’s problem, the leakage usually arises from many things. The leak sometimes causes steam-like substance to come out of the car bonnet.
Sometimes you can tell there is a leak if you notice coolant or water underneath the car when it is parked at night.
Okiror advises that you quickly find the source of the leakage and work on it to avoid damaging other parts of the radiator due to the excess heat.
According to Edmunds, a car website, heat is the enemy of your engine. If you’re getting indications from your dashboard that your car is running way too hot, or if you see or hear or smell something indicating excessive heat, it generally means one of two things. Either there is something seriously wrong with your engine, or the cooling system is not doing its job properly.
“Either way, you have to be very careful about driving the vehicle until you solve the problem. An overheated engine is a severe problem.
If you are driving your car and your water temperature gauge rises, and stays, in the red for any length of time, you must pull over immediately and call your mechanic or have the car towed.”
Car owners can also suffer from poor cooling systems when the fins get blocked. The fins help in cooling the fluid running to and from the engine.
It is advisable that you clean the fins each time you take the car for service to make sure there is no blockage within the system.
Other things to look out for in the car are the thermostat. The thermostat resides under the return hose that runs from the engine back to the radiator; this hose usually comes off the top of the engine.
Let the engine cool, remove and replace the thermostat, then run the idling test again. If that does not fix it, you will have to check out the water pump or the radiator.

Signs of a faulty radiator

In general, leaks and overheating are the most noticeable signs of failure.
However, simple leaking hoses and loose parts can cause both problems, and it is important to pay attention to other indicators of failure.

Leaking
One of the most obvious signs of a radiator problem is a pool of liquid forming beneath the engine when the car is not in use.
Leaky radiators require immediate attention, as they can cause serious damage. Radiator coolant fluid looks green or red in colour and is slimy in texture.
Other types of fluids under the vehicle are signs of different problems.
Overheating
Because the radiator’s main job is to keep the engine cool as it runs, even minor overheating is a major sign that something is wrong.
The problem is usually just a simple leak, but overheating is sometimes a sign of bigger problems, and it is important to investigate the problem.

Drop in pressure
If the radiator has a lot of corrosion, it produces lower pressure levels than normal. If those levels are lower, a problem exists.
Car owners can use pressure gauges to determine the pressure. These devices fit on top of the radiator cap and gauge pressure as the engine runs.

Low Coolant Levels
If the coolant levels are low, the radiator probably has a leak.
Coolant naturally depletes over time, but sudden drops in the coolant level are not normal.
Car owners should check hoses and connections to make sure everything is tight. If those parts look like they are in order, the system could have a hole somewhere.

Rust
Rust on or around the radiator indicates a leak or corrosion.
As the liquid leaks, it heats up and causes the metal to rust.