Overheating is a common problem with most cars especially in the big cities like Lagos, where one gets stuck in traffic for hours. It is not uncommon to see cars smoking from the bonnet. Adeniyi Balogun throws more light on its meaning, causes and prevention below:

Last time out, the engine cooling system and mode of operations were discussed as well as it’s various components that must be in place to maintain the optimum and desired cooling a car needs for efficiency. Today, the concept of overheating, it’s meaning, causes and prevention will be looked into.
Overheating: An engine must work optimally and efficiently at a certain temperature. Most cars are designed to operate at around 80 – 90°c. At this temperature, fuel consumption is at its best and engine works almost perfectly. The temp gauge also stays at the middle mark. 
Overheating is a symptom of a problem. Getting to the root of this problem is very important in “killing” the ultra headed monster called overheating. This simply happens when the temp of the engine via the gauge climbs to a point where mechanical damage can occur. Usually, a sustained temp of over 115°c is enough to cause concern. Steam coming from the engine area, a temp gauge rising to the red zone, and engine warning lights are signs that a car may be overheating. The method used by roadside mechanics to combat overheating by removing the thermostat and running the cooling fans direct may eventually renders the engine doomed as this marks the beginning of an end of that engine.

Causes: 
There are several causes of overheating. As earlier said, overheating is a symptom of a problem and if the root cause is not resolved, it will persist.

1. Too little or no coolant: The practice of using water in place of coolant for your radiator is very wrong. Water has a higher rust tendency and when this happens, radiator cells get blocked in a matter of time. Also, water boils at 100°c. Coolant has anti-rust compounds and most brands boiling point ranges from between 120°c – 140°c. With this, a coolant absorbs more heat than using ordinary water. Water may be used as an emergency need but must be flushed out and replaced with the vehicle’s recommended coolant as soon as the issue is resolved. Improper levels of coolant in the reservoir is a main cause of engine overheating.

2. Cooling system leaks: Leaks could be from the radiator, hoses, water pump or from the thermostat housing. These are external leaks. Internal leaks occur from the head/top gasket area. A coolant pressure test is advised if the source of the leak is not visible.

3. Broken water pump: Frequent use of water as coolant goes a long way in destroying the components of the cooling system, particularly the water pump and radiator. Sediments due to rusts from the engine block and radiator forms a thick buildup on the water pump and this in turn restrict circulation as the pellets of the pump get stuck. 

4. Radiator clogs or leak.

5. Oil too low or dirty: Asides lubricating the engine parts, a vehicle’s motor  oil helps control overall temperature. Low oils may increase engine temperature.

6. Thermostat failure: It’s function is to regulate engine temperature. It “opens” and “closes” with the aid of a sensor called the “coolant temperature sensor”. If it is stuck/closed, then there is a problem. Coolant does not circulate and this causes overheating. If it remains in open loop, then, engine runs cold and may take a long time to get to it’s desired temperature mark for optimum performance. The result is a higher fuel consumption and high carbon build up in the engine.

7. Hoses leaks 

8. Heater core plugged up.

9. Transmission (gear) issues: Yes, this is another “underrated” cause of engine getting abnormally hot. When the gear does not shift as it should, power becomes lost, then the  engine works harder. A hard working engine demands more power and this makes engine run hotter.

10. Brake binding : Another underrated cause of overheating. Brake works with the principle of hydraulics. When the brakes bind, the caliper refuses to return after braking. It gets stuck to the brake disc, preventing  the wheels from spinning freely. This could be caused by rust buildup in the brake caliper, or brake  flex hose blockage or even from the brake master cylinder or brake lines.

Prevention:
1. Regular flushing of the Cooling system to prevent rusts, dirts and mud buildup.
2. Change engine oil at recommend intervals
3. Use of coolant instead of water.
4. Monitor your temperature gauge on the dashboard. When needle is above the center mark, park safely and inspect.
5. Service brakes regularly, especially if you drive through flood most times or vehicle sits for a long time.
6. Never remove the engine thermostat. Always change at the specified mileage.
Conclusion:
Taking chances with your car if it starts to overheat could cause a whole lot of issues from, constant misfires, to burnt head gasket, to outright engine damage. Contact a certified auto tech with  pressure tests equipment for inspection whenever you sense your engine runs hotter than normal.

Written By Adeniyi Balogun