What Causes Car Engines to Overheat?

Educational

Sep 22nd, 2020

What Causes Car Engines to Overheat?

Don’t wait for a burnt smell or cloud of smoke (more likely bursting steam) to tell you about an overheating car engine. The temperature gauge on the dash should warn you earlier with a red H. 

Allowing the issue to linger can cause irreversible damage to the engine, so timely action is crucial. Read on to learn more about what causes engines to overheat, and what you should and should not do if you suddenly find your gauge spiking into the red zone.

5 Reasons Why Engines Overheat

Overheating happens when a car’s cooling system fails to do its job of absorbing and dissipating heat. You may learn more about how the automotive cooling system works to understand better what causes engine overheating. Here are five of the most common reasons. 

  1. Presence of leakages – if you had to replenish the coolant more often lately, it could mean that you’re losing coolant faster due to leaks in the system. If you suspect this, you need to get your car inspected immediately for seepage, loose gaskets, or cracks that can cause the coolant to escape. The problem could be anywhere from the water pump, reserve tank, heater core, thermostat, and all the hoses and gaskets.
  2. Using incorrect coolant – it’s important to refer to your car’s manual for the correct type and concentration of coolant for your vehicle. Using the wrong type or incorrect mixture can cause an inefficient cooling system, or worse, damage it. Make sure that your car’s regular servicing includes a check-up on possible corrosion and contamination in the system. Coolants break down over time, becoming inefficient and even causing corrosion, so periodic flushing of the system should be done at least every five years.
  3. Stuck thermostat – the thermostat has two positions, open and closed, which control the passage of the coolant as certain temperatures are reached. When it's stuck in the closed position, the hot coolant will no longer be able to go through to the radiator to cool off, causing the engine to overheat.
  4. Problems with the radiator – make sure there are no clogs or leaks in the radiator that will possibly disrupt its critical function of heat-exchanging. See to it that the radiator fan is working properly and pulling enough air to the radiator. If not, inspect the fan motor or clutch and look for signs of damage or wearing out. Clogs in the hoses will prevent the hot coolant from escaping the hot engine compartment or the cooled liquid from circulating back to the engine passages to do its cooling function. 
  5. Worn-out or leaky water pump – a bad water pump will not be capable of efficiently circulating the coolant. See if the pump has stopped working or id there’s any damage to it. Also check for wear in the pump belt, which is responsible for maintaining the correct flow or volume of the coolant. Don’t ignore noises that come from the driver’s side of the engine – these are signs of water pump damage. Remember, not all cooling system issues show as clouds of bursting steam.

What to Do When You Notice Signs of Overheating

Hopefully, you take heed of the ‘H’ warning on the dash before you overheat the engine past its saving point. Listen for noises in the engine and smell the strange odours (burnt or unusually sweet) coming from the engine area. And never miss those signs of steam or vapour rising from under the hood or that unmistakable red dash warning. Here’s what you should do:

  1. Turn off the air conditioning system. The engine drives the AC compressor, and by turning the AC off, you’re lightening the engine’s work and reducing the heat it produces. 
  2. Turn the heater's dial to hot or the max setting. The heater core works like a small radiator that draws heat from the engine and uses this heat to warm up the cabin and defog the windows in freezing weather. Crank it up with the fan at full blast to pull away as much heat from the engine as possible. Never mind that it’s going to make you all warm and toasty, as long as it will buy you some time to find a safe place to park without damaging the engine. And, do open the windows for your sake! 
  3. Get off the road. As soon as it’s safe to pull over, do so. Let the engine cool down while deciding whom to call for assistance in towing your vehicle. 
  4. Add coolant. When the gauge indicates that your engine has cooled sufficiently, check the coolant level. Top it off, if you think it’s lower than normal. Bear in mind that even if you have topped up the coolant, you can’t drive the car far if it has a bad radiator or pump, or it has a leak or clog. It’s best to have it towed to the nearest shop.
  5. Head for the nearest auto repair shop. If there’s no chance of tow assistance, try restarting the car and head for the nearest mechanic or shop. If the signs of overheating showed up again before you reach it, pull over and allow the engine to cool again. 

What Not to Do When Your Car Overheats

  1. Keep your cool even when your car is hot. Don’t swerve or stop abruptly. Always consider other road users as you pull over to a safe spot. 
  2. Don’t push your engine. It’s tempting to continue driving, especially if your destination is just a kilometer ahead, but don’t. Don’t go on thinking ‘Just a little bit farther’ because it won’t do you any good. You need to stop, allow your engine to cool, and assess the situation.
  3. Don’t pop the hood right after pulling over. Wait for the temperature gauge to normalise. There’s no point putting yourself at risk of steam burn on top of your car problem. 

As soon as your car is towed, find a way for the problem to be diagnosed and repaired. If any of the system parts are damaged or worn-out, you should get a car part replacement. It’s wrong to think that it will resolve on its own. Even if you get to your destination safely without towing assistance, the incident is already a fair warning that something is causing the engine to overheat. Find a mechanic near you now and locate a reliable seller of car parts within your suburb! 


By JMSL