The Sunday News
Lovert Mafukure
Heat is essential for survival. Too much heat on the other hand is bad for survival. Engines generate a lot of heat hence the need to have an entire cooling system set aside just to cool down the engine so it performs at its best.
Engines perform better when hot but the temperature should stay at an optimum range. If the engine runs cold, you get bad fuel economy, and accelerated wear and tear, If it’s too hot you damage the engine. The cooling system consists of the radiator, water pump, cooling fan and something called a thermostat. These make up the most important parts of the system. Machines are delicate things; they require extra care for continued functionality. If any of these is not working properly . . . you will have trouble in paradise.
The primary purpose of a radiator is to cool the coolant by way of conducting heat away from the coolant. Water circulates around the engine block and flows to the radiator for cooling. The water pump pumps the coolant back and forth from engine to the radiator to maintain the engine operating temperature. The cooling fan is there to push air through the radiator fins to cool the coolant. Without it, the engine may overheat. The thermostat on the other hand regulates the flow of coolant to the cooling radiator, it opens when the coolant is hot enough to be cooled a bit.
Causes of overheating
Engine overheating can be caused by a lot of things. I will look at the common causes. Firstly every car comes equipped with a thermostat; its primary function is to keep the operating temperature in the engine. It keeps the coolant within the radiator until the engine is at its operating temperature then it opens for continuous flow of coolant to the radiator. It works like a valve that opens and closes according to temperature ranges. Like everything else man made, its prone to failure and when it fails it causes all kinds of serious problems. Oftentimes thermostats get stuck either open or closed. If it gets stuck open, it may not cause any immediate problems, just the engine will run too cool, you might find the temperature below the optimum range. If the engine runs cool it won’t perform as well as it should and wears out quicker than normal. It also takes longer to warm up. The effects usually are noticeable in cold weather. The worst is when it gets stuck closed, that means there won’t be any flow to the radiator, the engine will overheat and consequently get damaged.
Leaks in the cooling system also cause temperature issues in your engine. Always check that hoses are still in good shape and not broken. They affect the pressure in the cooling system as it is meant to operate at a certain pressure level. Loss of pressure will cause overheating. Radiator leaks and water pump leaks or any leak whatsoever in the cooling system should be attended to before anything gets damaged. You should start worrying whenever you find your temperature gauge going over halfway mark, get it checked.
A faulty water-pump can also cause overheating. The water-pump’s job is to circulate the coolant and pressurise the system. If the water-pump is compromised in any way it may not perform its job as it should, that is, it won’t circulate the coolant well resulting in overheating. Radiators also get blocked with debris and corrosive deposits over time. A blocked radiator affects the flow of coolant. Its job is to cool down the coolant and if it’s blocked or clogged,the flow will be affected resulting in overheating. It’s good to do a radiator flush every once in a while to keep it clean and remove rust that may have built up in the system. You may also want to replace the cap every once in a while with a new one.
The radiator cap is not just a lid. It’s a piece of art engineered to maintain pressure in the cooling system. Sometimes people forget to put back the radiator cap or they lose them and drive the car without a cap. That is just a recipe for disaster. There will be coolant loss and again the engine will overheat.
Effects of overheating your engine
Overheating can cause serious damage to the engine; sometimes it can completely ruin it such that it won’t be repairable. The most common effect is a blown head gasket. A blown head gasket will lead to other problems like continued overheating problems and also affect the cooling system. A leaking head gasket makes way for engine compression and gases to leak into the coolant passages and over-pressurise the coolant system resulting in burst hoses and radiators as the pressure will try to find an escape route. This is common with most ex-Japanese cars that have plastic radiator tanks.
Most cylinder heads are made out of aluminum and heat can affect them quicker than other metals. If an engine overheats, the head may possibly warp, meaning the surface will lose its flat shape. Overheating also affects the valves even to the point of breaking them. If the heat is excessive pistons and con-rods may be affected as well as the block, everything can just break-apart from thermal expansion.
Signs of a blown head gasket
White Smoke is a sign that your engine is burning coolant, fuel and oxygen. Usually when a car with a leaking gasket sits overnight, the next time you start it up it will blow out white smoke that clears out after a few minutes. That is a sign of a leak because as the car sits coolant leaks into the cylinders and gets burnt when you start up the engine.
Excessive loss of coolant with no visible leaks can also be a sign that you are burning coolant together with fuel due to a leaking head gasket or a leak in the coolant passages. Coolant and oil may also start mixing and the result is that milky residue in the radiator.
Lastly, Bubbles in the radiator or expansion tank may not also be a sign of a leaking head gasket as gasses will escape through the leaking head gasket to the cooling system. Sometimes even the hoses start to swell like they will burst because of the added pressure.
Whenever you start experiencing any of these symptoms, you may want to park your car and get an expert to have a look at it. Some of the things you can do them yourself and save yourself the trouble of listening to all kinds of hogwash from typical mechanics.
Lovert Mafukure is a Japanese Imports consultant. For comments or questions regarding all Japanese imports, spares and maintenance you can contact him on Whatsapp+263772339938 or email [email protected]
