How Much Coolant Loss is Normal?

Similar to how a car needs engine oil and fuel to work, having enough car coolant is also really important. When a car’s engine runs, it gets hot because of things like air-fuel mixture combustion, moving parts, making electricity, and using air conditioning. But the question is how much coolant loss is normal.

Air comes in from the front of the car through special vents or openings called Air Intake Systems. These openings are made to get as much air as possible, which goes over the engine and cools it down. While this air makes the outside of the engine cooler, there’s a special liquid called coolant that cools down the internal parts of the engine.

The main function of the coolant is to control how hot the engine gets. It makes sure the engine doesn’t get too hot in the summer and helps it warm up when it’s really cold in winter. It’s important to keep enough coolant in the car. Sometimes, the coolant level goes down for different reasons.

If your vehicle’s cooling system has no mechanical issue, you might still see a small decrease in coolant levels as time goes on. However, it is normal to have around 0.25% less coolant after six months, which is about two or three ounces per year.

If you find that the drop in coolant is greater than this when you check, there’s possibly a coolant leak. It is recommended to check and fix the possible leaks before adding more coolant.

Does Coolant Evaporate?

No, coolant doesn’t disappear by evaporating because it’s in a closed system. The coolant can’t evaporate due to the closed-loop design of the cooling system.

If you observe a slight reduction in the coolant level with time, it’s likely not the coolant evaporating, but rather the water in the mixture. Most coolant mixtures are half water and half coolant. Water tends to evaporate first, even if it’s in small amounts. If you see the level dropping, it’s more probable that your vehicle has a leak.

Causes Of Coolant Loss

Coolant loss may be caused due to different causes such as external coolant leaks, blown head gasket, damaged heater core, or internal EGR cooler leaks.

Let’s discuss the most common causes of coolant loss:

1) Blown Head Gasket

If you see insufficient coolant in your car, there are chances that your head gasket is blown – that’s a bad problem.

As the head gasket becomes faulty, oil and coolant may mix up. This issue can even crack the engine block or mess up the cylinder head, and sometimes you’ll see white smoke from the exhaust.

Fixing this issue is tricky, especially for older models, and it might cost a lot.

2) External Coolant Leak

The external coolant leak is one of the major causes of coolant loss. Various components in your cooling system may become faulty and cause leaks. For instance, if your radiator cap gets harmed or its seal deteriorates, it may result in a leak. Radiator hoses are also prone to failure and leaking.

Moreover, there’s a possibility of a leak originating from an issue with the radiator itself. Adding too much water with the coolant may speed up the process of rust and corrosion. These components of the cooling system are prone to wearing out on their own as time goes by.

3) Leaking Heater Core

The heater core is one of the most important parts of the vehicle. While coolant helps to protect the heater core from corrosion, it can eventually deplete, making the system susceptible.

If coolant leaks from the heater core, it can make the coolant levels go down, and this might cause engine overheating. You could also smell something sweet within your vehicle, and it might be harder to make the vehicle warm up.

4) Internal EGR Cooler Leak

The EGR cooler plays a crucial role in the exhaust system of your vehicle, but it’s also susceptible to malfunction.

If the EGR cooler is leaking internally, you might see coolant coming out of the tailpipe, along with white smoke. The car’s check engine light might turn on, and the coolant level might keep getting lower until it’s fixed.

How To Fix Coolant Loss

Regardless of the cause of the coolant leak, it’s usually possible to repair. There are situations where you could diagnose and address the issue on your own, but there are also times when you might require additional assistance.

Follow the below-given steps to diagnose and fix the coolant loss:

1) Replace Head Gasket

Diagnosing a blown head gasket isn’t straightforward. Many individuals prefer to assess symptoms to gauge the likelihood of a head gasket failure. Signs might include seeing oil in the coolant or vice versa, along with white smoke from the tailpipe.

If these symptoms point to a faulty head gasket, you can dig deeper into diagnostics. But unless you’re experienced, it’s not advisable to proceed with these steps due to potential risks.

Here are some general steps to follow, with extreme caution.

Allow the car engine to reach operating temperature.
Switch off the car and cautiously remove the radiator cap.
Position a funnel where the radiator cap was.
Restart the engine.
Observe the coolant flow. If you notice a substantial number of bubbles, it could suggest a potential gasket failure.

Due to the possibility of hot coolant splashing from the radiator, you might not be at ease performing this task on your own. If that’s the case, contact a professional.

2) Fix Coolant Leaks

Before you can address a coolant leak, you need to locate it. The simplest method to identify a coolant leak is by observing external drips. Put a big piece of cardboard beneath your car overnight. In the morning, you can see where any coolant drips are on the piece, which will help to find the location of the coolant leak.

Look under your car and check where the leak is happening. Focus on the clamps and hoses since they can get worn out. Also, check the radiator and other parts of the cooling system for possible repairs.

3) Use A Cooling System Sealer

In case of a gasket leak, hose, or radiator, there’s an option to temporarily employ a radiator sealer or cooling system sealer. These sealers introduce a chemical into the system that seals up small leaks. Utilizing these products is straightforward and budget-friendly.

Follow the below-given instructions to apply the cooling system sealer:

Purchase a reputable radiator sealant; avoid opting for lesser-known brands. Invest a bit more in a reliable product.
Empty the sealant into the radiator, adhering to the instructions on the label for the correct amount. Usually, you’ll need to use the entire bottle.
If coolant levels are low, add more coolant. Otherwise, if levels are already normal, no additional coolant is necessary.
Initiate the engine. Allow it to warm up and enable the sealant to circulate. It’s advisable to keep the engine running for around ten minutes.
Refrain from driving overnight. Once you’ve followed the steps, leave the car untouched overnight. Ideally, avoid driving the car for approximately 12 hours to allow the sealant to be properly set.

Keep in mind that sealants can’t permanently fix the leaks. While a dependable sealant can offer temporary relief, it’s crucial to have the cooling system professionally inspected and fixed.

4) Contact A Professional

If you are unable to find or fix the issue, seeking help from a professional is advisable. Cooling system problems can be complex to diagnose and resolve, so it’s best not to take risks if you lack the necessary expertise.

Fixing a blown head gasket, for instance, is a challenging task that requires specialized tools and knowledge, making professional assistance essential. Therefore, seeking additional guidance is recommended.

Is It Normal for the Coolant Level to Drop?

Yes, a slight reduction in coolant level is usual, although minimal. Numerous factors contribute to heightened engine temperatures, including internal combustion, continuous motion of diverse mechanical components, and power production.

Consequently, the coolant manages the heat generated during these activities to avert engine overheating. As a result, the water content within the antifreeze mixture might evaporate, causing a decrease in the coolant level.

FAQ Section

What does the loss of coolant mean?

Loss of coolant represents a condition where the coolant responsible for cooling the engine is reducing or leaking from the system, possibly causing engine overheating and other issues.

Can I lose coolant without leaks?

If your coolant level naturally decreases, it should be to such a slight extent that it’s hard to detect. Coolant doesn’t typically evaporate as it flows within a sealed system. If you’re experiencing a consistent drop in coolant levels, it’s more likely due to a leak in the cooling system. In this case, it’s important to inspect the system and repair the issue.

Why am I losing coolant without any leaks?

When coolant levels decrease, and no external leak is found, it is possible that there is an internal leak. If your head gasket is faulty, coolant might be leaking into the engine cylinder and mixing with the car’s oil. This is a critical issue that requires immediate attention.

What happens if the coolant level is low?

Continuing to drive the vehicle with coolant levels below the recommended minimum may lead to costly damage. A sufficient amount of coolant is crucial to prevent the engine from overheating. If the coolant level keeps dropping, potentially causing the water pump to fail. This failure would result in the inability to circulate coolant from the radiator to the engine compartment for cooling purposes. As pressure builds up, a chain reaction can occur: from engine head cracks, coolant vaporizing, gasket failure, and eventually, engine seizing unless preventative measures are taken.

Should I worry about a small coolant leak?

In the case of a minor leak, you may consider continuing to drive, assuming it’s not a big concern. However, it’s essential to recognize the risks. A coolant leak poses dangers to the environment, pets, and children. Beyond these considerations, even a small leak has the potential to escalate into a significant issue. For instance, if a hose were to burst while you’re on the road, you could suddenly lose all the coolant, resulting in engine overheating without any prior warning.

What causes coolant to leak internally?

A blown head gasket is one of the major causes of internal coolant leakage. The head gasket forms a seal around the engine cylinder. It prevents the engine coolant and oil from entering the engine cylinder. Without this protection, severe and expensive damage can occur to your engine.

How often do you need to top off coolant?

Regularly check and top off the coolant level whenever it becomes insufficient. If you consistently find the coolant to be low, it’s wise to check the system for leaks. On the other hand, many car manufacturers recommend changing the coolant either after every four years or 60,000 miles, depending on which comes first. Consult your car’s owner manual for precise recommendations.

What causes loss of coolant?

Loss of coolant can be caused by different reasons, such as a faulty water pump, an issue with the radiator, blown gaskets, or damaged hoses.

Written By

Engineer Rahela

Rahela is the owner and main author of Mechanicalspecial. She is an automotive expert writer. She have over four years of experience in the automotive writing niche and have completed over 700 pieces of content from 40 projects. She have good knowledge and skill in vehicle repairing, all mechanical work, car upgrades and maintenance.

How Much Coolant Loss is Normal? | Causes Of Coolant Loss