Engine classification

Engine Overheating: Symptoms, Causes, And Solutions


Engine overheating? Top 10 tips to troubleshoot

There are multiple reasons why your vehicle’s engine overheats or its temperature shoots up. In this article, we look at the common causes and solutions for engine overheating.

Warning signs & symptoms of overheating:

  1. Only after driving a short distance of travel, the engine starts knocking severely.
  2. The engine may stop suddenly. You are able to crank the engine but, it does not start. It starts again with some noise after it cools down a bit.
  3. To prevent the engine from overheating, you must switch-off any additional load on the engine. Vehicular systems such as air-conditioning, power steering, and alternator draw power from the engine. However, you cannot disconnect the alternator and power-steering system from a running engine. So, firstly shut off the car’s air-conditioner.
  4. To reduce the effect of engine overheating, keep your engine rpm at the lowest possible. This would not damage the engine parts any further. Move your vehicle to a safe place/parking lot, possibly off the road and well-lit area. Thus, it will be easier for you to diagnose the engine overheating issue. Now, switch off the engine by keeping the key in the “ignition on” mode. This way, it will keep the engine and a/c fan running. Most modern-day cars have electric cooling fans that stay ON even when you switch off the engine. Now, pay particular attention to the fan kicking noise as you will hear. This information will help you later in the engine overheating diagnosis.
  5. Now, make sure that there is no obstruction in front of the radiator that is blocking the airflow. It could be a piece of a foreign object such as dry leaves, paper or polythene bag. If found, remove &/or clean the grill area. Then, open the bonnet. This will disperse the heat quickly. If you see the hot steam coming out from the bonnet area, stay away from it. Wait for the heat to decrease completely and call for a mechanic.
  6. When the car is standing still, the engine will not get sufficient air-flow assisting the cooling system. Hence, it is very tough for the engine cooling system to keep the engine under control. Following the above steps will help minimize the damage.

Engine Overheating Occurs If the Radiator is Empty:

Notice the coolant auxiliary tank (coolant storage). Generally, it is a small plastic tank which stores the coolant. If you notice that the fluid level is below the minimum mark, it is possible that your radiator level may also be lower than necessary. Top up this auxiliary tank with coolant or distilled water.

In some cars, the auxiliary tank is pressurized. You will notice a warning around the tank’s cap. If the cap needs to be screwed off (not flipped open), then it's pressurized. Don't open the cap in that case and wait for the engine to cool down.

Caution: Never open the
hot radiator with bare hands because the system is still hot and pressurized.
Opening the radiator cap will spray out the pressurized coolant like a volcano.
If you are in its path, it will seriously hurt you. The heat in the pressurized
steam will give you severe burns than hot liquid. Steam burns are even more severe
than boiling water burns. Additionally, keep your face out of the way as a
precaution.

Remember, you should NOT open the radiator cap when the engine is hot. It's like a pressure cooker. So, you could end up severely burnt. Therefore, wait for about a minimum of 30-40 minutes. When the engine becomes cool, slowly open the radiator cap by placing a thick cloth over it. You need to do this very slowly as there might be some excess pressure and steam inside.

Take the following action while dealing with the overheating issue:

If the radiator is dry, top it up with coolant and/or water. If you do not have coolant, use only water as a temporary measure. First and foremost, start the engine before you start filling the radiator. This is necessary to remove any air trapped inside the engine. Or, else your engine block may crack. Let the engine run at idling and slowly top-up the coolant and/or water. Let the engine idle with the radiator cap open so that the trapped air escapes.

Other overheating causes are:

  1. A faulty radiator pressure cap
  2. Snapped fan belt (in older cars)
  3. Blown cylinder head gasket
  4. Broken Water pump shaft
  5. Faulty engine temperature sensor
  6. Incorrect ignition timing

Engine Overheating causes:

  1. Generally, a modern car's radiator will not get completely dry. However, if the car’s radiator is dry, it indicates a faulty fan or leakage. Was the fan working when you stopped the car with the "ignition on" mode? You need to double-check this. After you fill-up, the radiator, start the engine again. After a few minutes (3-5) of idling, the cooling fan should automatically start when your car engine reaches the operating temperature. If it doesn't start, then there is a problem. Now, turn the air-conditioning on (if fitted). Most modern cars will start the radiator cooling fan the moment you switch on the air-con.
  2. Now, check the fan fuse. If it's blown, replace it.
  3. Even with a faulty cooling fan, your engine could maintain its optimum temperature when cruising on highways. Thus, you will be able to reach the nearest service station. However, if you stuck up in traffic, the engine cooling system won't be able to cope with it. Hence, you should avoid heavy traffic conditions so far as possible. Keep filling your radiator and stick to highways/motorways. Maintain the highest gear & lowest engine rpm possible. Switch off the engine whenever you halt (e.g. at a traffic light). Keep a close eye on the temperature gauge. If it comes close to the maximum level (red), then turn the engine off.
  4. In some older designs, the crankshaft itself drives the water pump by a belt which also drives the alternator in most cases. If you see the charge light remaining on while the temp gauge rising, then a snapped belt is mostly the cause.
  5. The crankshaft drives the water pump by the timing belt which sits inside the engine block. The water pump shaft might snap and/or its impellor might fail.
  6. A faulty sensor will send the wrong signal to ECU. In this case, it will show the maximum reading even when the engine is cold.
  7. Incorrect setting of timing may also lead to engine overheating. In this case, the engine may unusually knock.

For more information on the engine systems, please click here.

Read More: How engine lubrication system works?>>

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