The internal combustion unit of the engine produces a lot of heat, sometimes temperatures exceed 200 degrees. Therefore, it is important to control this heat by using a cooling system.
A car’s cooling system is a sealed system, meaning the coolant level must remain even if everything is working as it should.
Unfortunately, cars are not always known to be problem-free and as a result, problems can occur, which can lead to low coolant levels.
But is it safe to drive with low coolant? what causes it, and how to recognize it without opening the hood? Let’s find out! But first, let’s look at the reasons why your coolant level is low:
The most common reason for low engine coolant is almost always due to leaks in the cooling system. Leaks can come from leaking pipes, sensors, or seals. Simply topping up the coolant level should never be a long-term solution.
You will find more possible symptoms later in the article, but first let’s look at the consequences of driving with low water level in the engine.
Consequences of driving with low coolant level
The most common consequence of driving with low coolant is air in the cooling system, which causes the engine to overheat. An overheated engine can cause a blown head gasket or damaged engine block.
Here is a more detailed list of what can happen if you ignore and drive with low-engine coolant:
1. Air in the cooling system
The first thing that could happen if you are driving with low coolant is the water pump pumping air into the cooling system and causing air pockets in the cooling system.
Airlocks disrupt the flow of the cooling system and cause the engine to overheat, which we will discuss in more detail in the next section.
2. Engine overheating
Due to the air pockets in the cooling system that we discussed earlier, the water pump will not pump coolant to keep the engine at the proper temperature, and this will cause the engine to overheat.
An overheated engine can cause many costly problems with your engine, which we will discuss in the following sections.
3. Blow the head gasket
A very common and not-so-fun thing that can happen when your engine overheats due to low coolant is a blown head gasket.
The head gasket is located between the engine cylinder head and the cylinder head; Its purpose is to separate compression, oil, and coolant. Replacing the head gasket is usually quite expensive and you can expect repair costs of over $1000; However, that is nothing compared to what comes next.
Related: Symptoms of a bad head gasket
4. Damaged engine block
An even more serious problem that can occur if you drive with low coolant is a damaged or cracked engine block. As we told you before, low coolant can create hot spots in the cooling system.
These hot spots can cause extreme temperatures in the engine block, which can actually cause it to crack, and a crack in the engine block or cylinder head is the last thing you want. To repair it, you must replace the entire engine block.
5. Engine seized
Most engine parts are made of metal, and as you may already know, metal expands and contracts with temperature. If the engine does not maintain temperature properly, engine parts can expand so much that they become damaged and the engine will stop.
Most of the time, the only way to repair a seized engine is to disassemble the entire engine to locate the problem.
Is it safe to drive with low engine coolant?
No, it is not safe to drive with a low coolant level. Low engine coolant can cause air pockets in the cooling system, and an overheated engine can destroy expensive parts like the engine block or seize it entirely.
Refilling engine coolant is such an easy thing to do and it’s certainly worth considering the consequences. Just be careful to never open the coolant reservoir when the engine coolant is hot!
Symptoms of low coolant level
The most common symptom of a low coolant level is a coolant level warning symbol on the dashboard. If your temperature gauge fluctuates, it may be due to low engine coolant.
The easiest way to tell if your engine coolant level is low is, of course, to open the hood and check the coolant reservoir.
However, there are other things you can check. Here is a more detailed list of the most common low coolant symptoms:
1. Low coolant level symbol on the instrument panel
Most modern cars have a warning light that will appear on the dashboard if the engine coolant level is low. It may seem obvious, but not all car models have this light, especially if the car model is a little older.
If a low engine cooling system appears on the dashboard, it’s definitely time to check the coolant level.
2. Fluctuating temperature indicator
Another symptom of low engine coolant that you will notice is that the engine temperature gauge may begin to fluctuate rapidly between different temperatures.
This happens when the engine coolant level is so low that air is pumped into the cooling system. When an airlock surrounds the coolant sensor, it drops and when the coolant returns, it returns to normal temperature.
3. Rising temperature indicator
When the engine cools normally, the temperature gauge on the instrument panel will be below half. If it exceeds the engine’s operating temperature, the problem needs to be resolved quickly.
If your temperature gauge exceeds the normal operating temperature (200 Fahrenheit or 90 degrees Celsius), you must shut off the engine or risk overheating.
4. The heating does not work
The car heater uses the same coolant that circulates through the engine. Valves are used to control the entry of coolant into the car; therefore, temperature regulation.
If your heater is not working as expected, you may be low on engine coolant due to air pockets in the heater core.
5. The sweet smell of antifreeze
Antifreeze is a compound included with coolant to prevent water in the radiator from solidifying during cold seasons.
A distinctive feature of antifreeze is that it has a sweet smell. If you notice that your engine produces a sweet smell, the cooling system has a leak.
Causes of Low Engine Coolant Level
The most common cause of low engine coolant is external coolant leaks, but it can also be missing from other places.
Here is a more detailed list of the most common causes of low coolant:
1. External coolant leak
As we said before, the most common cause of low engine coolant is external leaks. External coolant leaks can come from any part of the cooling system. Fortunately, external coolant leaks are often visible and you can easily determine where the leak is coming from.
Common external leaks are from the water pump, radiator, or around the thermostat.
2. Defective intake manifold gasket
Many intake manifolds cool the intake air with coolant and therefore have coolant channels inside them. Therefore, a gasket is installed between the intake manifold and the cylinder head.
This gasket can begin to leak and the engine will suck in and burn coolant. You can often recognize this by seeing white smoke coming from the exhaust pipe.
Related: 5 Symptoms of a Bad Intake Manifold Gasket
3. Defective head gasket
Another thing that can cause low engine coolant is a bad or blown head gasket. As we said before, the head gasket separates compression, oil, and coolant.
Therefore, a bad head gasket can cause coolant to mix with compression, which will cause the engine to burn coolant. Additionally, this is easier to recognize by looking for white smoke in the exhaust pipe.
4. Defective radiator cap
Inside the radiator cap, you will find a pressure relief valve that will open if the pressure exceeds a certain pressure. If this valve is defective, it may open before this pressure and this will cause a refrigerant leak.
You can often see this by looking for white smoke coming from the engine compartment.
Related: 6 Symptoms of a Bad Radiator Cap
5. Defective EGR cooler
The last thing on this list that can cause low engine coolant is a crack inside the EGR cooler. Not all car engines have EGR coolers, so you first need to find out if your engine has one. They are mainly found in European cars.
A faulty EGR cooler will cause coolant to leak into the exhaust pipe, which will also cause white smoke from the tailpipe.