Why Is My Coolant Leaking? (9 Reasons Why)

Although coolant leaks may not appear serious, they could put the engine of your car in danger. Your engine may overheat if the right amount of antifreeze isn’t used. 

Coolant must be checked frequently because it is so important to how effectively your engine performs. 

This is particularly true for older vehicles, which might not function as well as more recent models. So, learn more about why your coolant is leaking!

Why Is My Coolant Leaking?

Radiator hose or radiator leaks are the most typical causes of why your coolant is leaking. It might also be brought on by a malfunctioning expansion tank or water pump. Leaks surrounding hose clamps, as well as from breaks in plastic pipes in the cooling system, are also fairly typical.

Learn more about why your coolant is leaking. Here are nine reasons why. Continue reading for further information!

1. Expansion Tank Issue

Your car has an expansion tank, which is a plastic container next to the engine, to aid provide coolant to the radiator. 

It typically has a rubber hose connecting it to the radiator, and as the engine warms up or settles down, it feeds or gets coolant from and to your vehicle’s radiator.

That plastic may deteriorate with time and response to temperature changes, which could also affect the parts that are attached to it. 

The cap or container could shatter, allowing coolant to flow out. Another possibility is that the hose connecting to the radiator starts to deteriorate, which results in a bad connection and a fluid leak.

2. Faulty Water Pump

In order to make sure that coolant is circulated all across the cooling system, the water pump is essential. 

Read More:  Why Are My Car Speakers Crackling? (11 Reasons Why)

It is situated in the lower portion of the engine, next to the drive belts, and is often powered by a belt. 

Also, it is connected to the radiator’s bottom hose, although occasionally, that hose attachment can come unfastened or corrode.

Additionally, it could sustain external damage of some kind that results in a leak.

Your engine will eventually overheat if a water pump issue hinders it from circulating coolant all through the system, regardless of the underlying cause.

3. Damaged Or Blown Head Gasket

How well the engine operates is greatly influenced by the head gasket of your car. You might not notice a head gasket blowing for a while. 

The head gasket must endure a wide variety of temperatures as well as extremely high and extremely low engine pressure. 

It is known to be “blown” whenever it creates a leakage and is located among the cylinder head as well as the engine block.

That makes it incapable of keeping the coolant and engine oil separate, which is exceedingly dangerous and can result in engine failure. 

Additionally, it may cause coolant to leak beyond the engine; as a result, your car’s cooling capacity may decline as the coolant level does.

4. Damaged Radiator Cap 

Despite being small, the radiator cap serves a significant function. 

The cap is in charge of forming a good seal that maintains the cooling system’s proper pressure despite the radiator’s high pressure. 

Further, the spring may begin to wear down or the seal may weaken with time, allowing coolant to leak.

5. Radiator Hole

Radiator Hole

All of the engine components in your automobile must withstand a great deal of wear and high temperatures, and this damages them in different ways. 

Read More:  Why Is My Check Engine Light On? (20 Reasons Why)

One of the main causes of coolant leaks is internal radiator corrosion. You might obtain silt or debris within the tubes as they age and become weaker, which leads to a leak. 

Another component that could wear out and cause a leak is the gasket that seals the tank to the radiator.

The hoses that are attached to the radiator may also be to blame; as they age, your hoses will get brittle and tough and won’t close as well. 

They all become susceptible to leakage at the points where they link to the heater core, water pump, and radiator.

6. External Leak

The most frequent cause of external auto coolant leaks is radiator hoses. A little fracture can allow liquid coolant to leak out. 

It could be more challenging to identify a leaking radiator than a leaking radiator hose. Frequently, the radiator will need to be taken apart in order to check for bubbles. 

The closed tube system that makes up the radiator. The tubes should all have a smooth liquid flow. Anywhere on your radiator that there are bubbles, there is usually a leak.

7. Internal Leak

In contrast to external coolant leaks, internal automotive coolant leaks do not typically result in a coolant pool directly beneath the vehicle. 

Further, the liquid coolant storage needs to be refilled more regularly than it used to, as you will observe. 

Oil and engine coolant is kept out of the combustion chamber by a head gasket. Exhaust gasses are also included in head gaskets to help keep the engine running efficiently. 

Read More:  Why Does My Truck Jerk When I Accelerate? (9 Reasons Why)

In addition, high-pressure and hot combustion gasses are present within the engine. The liquid coolant is located inside the engine but outside the combustion chamber. 

The head gasket may deteriorate and start to leak over time. You can inspect to see if coolant collects directly beneath the exhaust manifold and if the leakage is external. 

8. Loose Clamp

Clamps are used to join the radiator’s hoses. To secure the connections between the radiator and hoses, these clamps wrap around the hose and are secured.

Clamps of lower quality may rust if used. Your clamp won’t make a good seal if it is not securely fastened to the hose. It will then be possible for the coolant to flow through the broken seals.

It can be repaired and is very affordable. Just a few clamps must be changed. Use high-quality clamps to prevent further corrosion.

9. Broken Heater Core

The heater core is traversed by the heated coolant. Once you turn on your heater, the heat would then be extracted from your coolant and circulated via your air vents.

The heater core replacement is the best remedy for this. The ideal alternative is a device with a copper core and an aluminum body. These are able to last longer.


Maintaining a regular maintenance program that involves changing the coolant in the radiator can effectively deter coolant leaks from happening.

Regular inspections might find other issues, such as loose or decaying hoses, that could cause a radiator to leak.

Leave a Comment