A hot engine usually spells trouble. Now, despite the heat, we can do everyday car-related tasks like refilling the oil. However, it’s never a good idea to ignore that heat; as soon as you spot that the engine is a few degrees below sizzling, you should definitely take action.
But why do car engines even overheat? What are some of the most common causes of this heat and how do we recognize it before something serious happens? With this article, I will try to provide answers to these hot-button issues. In addition, I’ll also list off all the ways in which you can make your engine cool down.
Common Causes of Engine Overheating
Cooling System Leaks
It honestly doesn’t get simpler than this: if my cooling system is on the fritz, the heat will be on the rise. And that’s not true with car engines alone. Any device, big or small, needs a decent cooling system since the working components tend to generate lots of heat, sometimes much more than the components can handle.
So, which particular leaks cause the car engine to overheat? Well, any number of them can be the culprit — radiator leaks, water pump leaks, leaks in different hoses, leaks in the thermostat housing, the head gasket, freeze plugs, heater core… Any number of these leaks can end up costing you a small fortune at the mechanic. But more importantly, they can damage your engine mid-drive, so you risk crashing somewhere and losing your life.
There are many valves that help the coolant pass through the radiator and reduce the heat in the engine. Possibly the most important one is the thermostat.
Usually, a thermostat opens and closes with no issues. However, there are times when it can get stuck in an open or closed position. Once it’s stuck closed, for instance, the coolant is stuck and it can’t pass through. It then slowly starts to overheat in the engine until it becomes a major problem.
Using the Right Coolant
As I stated earlier, an engine overheats if there’s a problem with the cooling system. However, there are times when there are no leaks, no stuck thermostats, nothing that’s immediately wrong with the engine. But for some reason, despite there being no issues with the mechanical components, the engine still overheats. Should this happen to you, you might want to check the type of coolant you’re using.
Coolant is a fluid that helps with keeping the engine running without getting heated above or cooled below a specific temperature. And since there are thousands of different brands of cars and car engines, there are thousands of different coolant types. So, the first thing you need to do is find the right coolant for your specific car. Anything that doesn’t match your specific model can lead to overheating, so do thorough research and get the coolant that fits.
Hoses can contribute to engine overheating due to several different issues. For example, if I were to buy a used car, chances are that I can face worn or cracked hoses. After years of constant driving, a hose can lose its former firmness and small openings will likely appear. Once they do, the coolant will start leaking all over the engine, leaving it without the necessary cooling.
But then again, what happens if the hoses don’t leak and if there is no visible outside damage? Well, the answer is not particularly difficult — the problem is inside of the hose. If you tend to drive often, dirt and grime can find their way to the inside of your engine, more often than not getting into the hose itself. Once they do, they accumulate and begin to clog the hose, preventing the coolant from getting to the radiator and leaving the engine piping hot.
In order to cycle the heat from the hot coolant into the engine, you’ll need a working radiator. If the radiator doesn’t work, both the coolant and the engine will remain hot throughout the drive.
There are various problems that can happen to a radiator. For example, it can get clogged up thanks to all of the outside elements like debris, dirt, sand, insects, or leaves. The obstruction will, at high speeds, enter the fin tubes that run across the front of the radiator. When this obstruction happens, not enough air can reach the radiator so it starts to build up a lot more heat than usual.
Alternatively, your radiator might have damaged fins. Each fin within the tubes is delicate and thin, so it can bend or break quite easily. In fact, the tiniest amount of sand or grime can cause damage to the fins while driving.
But there are other situations where this type of issue can happen. For instance, if you were to wash the radiator by spraying water on it, that same jet of water can bend the fins out of shape. In addition, you can damage them when you’re installing a brand new radiator. Whether you’re cleaning or upgrading your car, do pay attention and make sure the radiator is working properly.
Water pump belts are vital to any cooling system. They are usually serpentine rubber/nylon belts that operate the water pump, the power steering pump, and the compressor of your car’s air conditioner.
Because it’s made of such heat-susceptible materials, a water pump belt can become brittle over time and break. Alternatively, it can come loose for one reason or another. Any of these situations can lead to an overheated engine, so make sure to check your water pump belts.
Speaking of water pumps…
Water Pump Issues
Finally, we get to the very “heart” of any cooling system, i.e. the water pump. This pump is the part that allows the coolant to circulate throughout the engine. If you’re interested in how such pumps work, I suggest taking a look at this article.
Anything can go wrong with a water pump. For instance, if I spot leaks, I can assume that they came from a crack in the pump’s exterior. Also, the pump’s impeller vanes or the bump shaft might be the cause. Finally, it might just be the case of the pump not being properly (re)installed after a major tune-up.
Symptoms of Engine Overheating
Temperature Gauge/Light Warnings
A good place to start would be the temperature gauge on the dashboard. Sometimes it’s not a gauge, but a warning light, as is the case with my car.
When the engine overheats, the gauge will react, letting the driver know that there is extensive heat and that they should take care of it. However, there is one major issue with this indicator. Namely, it only shows the temperature of the coolant, not the engine itself. In other words, it will show nothing if there’s a coolant leak, which, as we’ve learned, can cause major overheating in the engine.
The Hood Is Hot
Engines will generate heat even when they work with zero issues. Therefore, it’s normal for the hood of your car to feel warm to the touch. After all, the engine had been heating it from underneath for…well, however long the last drive took you.
However, when the hood is piping hot, you need to pay attention. When I’m not sure about the heat, I place my hand on the hood and wait. If I can endure 10 seconds with no real issues, then there’s no overheating problem. Anything below 10 seconds is a cause for concern.
The Car Smells Hot
It might sound strange to inexperienced drivers, but there is such a thing as a “hot” car smell. That smell is actually a combination of several different scents that come from an overheating engine.
As it starts to overheat, all parts made from rubber, plastic, or resin slowly start to melt. During that melting process, the parts emit a combination of vapors that mix with the fumes from the burning oil inside of the engine. Another type of “hot” smell is the ethylene glycol that comes from leaking coolant. Unlike the other “hot” smell, this one has a bit of a sweet scent, but it can be extremely toxic if you don’t do something about it.
Obviously, the coolant will leak if there’s damage to any of the engine parts, as I’ve covered earlier. So, if you notice a little puddle of coolant under the car, you should see a mechanic at once.
However, that little puddle might actually be a direct result of an overheating engine. For instance, as it heats, the engine will boil the coolant within the radiator. Because of this process, the pressure within the tank builds up, so it starts to overflow in order to release the excess liquid inside.
Constant Ticking Noises
A solid sign of an overheating engine includes lots of quick, ticking noises while you drive. As the oil within the engine overheats, it stops acting like a lubricant and behaves like tap water. And without lubrication, the moving parts of the engine are clanking against each other, causing friction and lots of annoying sounds. These situations tend to occur during extreme heat waves, so always double-check your car if you have to drive somewhere in the middle of that scorching August noon.
Both quick, light ticking noises and loud, booming thumping can be signs of overheating. However, the source of the noise isn’t the same.
As I mentioned earlier, the thermostat helps the flow of the coolant to the radiator. It does so by controlling the valve that lets the coolant go back and forth. This valve can get stuck for a variety of reasons, and once it does, the coolant that’s in the engine block starts to superheat. Once this superheated coolant comes into contact with the cold coolant, they produce an extremely loud thumping noise.
Sometimes, boiling coolant will stay in the engine, and other times it will overflow and leak onto the floor. But by far the most critical point that coolant can reach in a heated engine is the moment when it boils and becomes steam.
Hot steam builds pressure within the tank. Once it reaches a certain point, it will escape the coolant reservoir or the radiator cap and start to “spill” from all sides of your engine. From outside, it will look like the whole underside of the hood is smoking. That right there is when you have to stop the car and step outside.
Insufficient Engine Power
If an engine starts to underperform, any number of things can be wrong. The reason I mention this symptom last is that it doesn’t necessarily point to engine overheating. Again, it can be any number of things, from a faulty car battery to an engine part going haywire.
So, how can I make sure that insufficient engine power is a sign of an overheating engine? Well, I simply combine it with other symptoms from this list. In other words, the moment I notice that the engine isn’t performing like it used to, I literally start to sniff around for any vapors or smoke. In addition, I check all the heat indicators and pause by the side of the road to check if the hood is too hot.
What You Should Do if the Engine is Overheating
Now that we have all of the symptoms and causes listed, let’s move on to actually solving the problem (or at least, walking away from it safely). One piece of advice that applies to everything I’m about to mention is this: always stay calm and don’t panic. Panicking can make you do something reckless and cause even more damage to your car, so tread carefully.
Switch Off the AC and Turn On the Heat
If you have nowhere to pull over during a drive while the engine is overheating, you can always mitigate the heat it generates. For instance, when my own engine was doing that, I turned off the AC first. It reduced the stress on the engine, allowing it to “calm down” a bit. Next, I turned up the heat; this might sound contradictory, but all the heat that enters the car is actually redirected from the engine.
The very second you find a safe spot along the road, pull the vehicle over. Lower your windows, open the doors, and wait roughly 15 minutes for the engine to cool down. In the meantime, make sure to check the temperature gauge and see if it’s going down.
Open the Hood Once it Cools Down
Earlier, I mentioned that the hood can get extremely hot if you have this type of engine trouble. So, once you pull over, wait for the hood to cool down, and then pop it open. A good idea is to keep the engine off, but leave the key in the on position; that way the fans will continue to cool the engine even if it’s not running. Make sure that a good 30 minutes or so go by before you touch the engine or the radiator cap.
These are the basic engine overheating tips;
What Not to Do
- Don’t panic or lose control of the vehicle
- Don’t continue to drive the vehicle while the engine is hot
- The hood will be piping hot, so don’t open it the second you pull over
- By no means should you continue to drive the car after the incident has passed; consult a mechanic at once
Overheating can be harmful to us in more ways than one. I always make sure that both my readers and my close friends know just how much danger they’re putting themselves in if they don’t address the heat issue. For that reason alone, I felt that this article was necessary and I hope you found it informative. Feel free to let me know what you thought in the comments below.