Can A Clogged Radiator Cause Overheating? Signs

The engine generates a lot of heat and needs a mechanism to self-regulate. Without this regulation, the heat can cause devastating damage to the car.

Manufacturers have devised a cooling system with a radiator to regulate the engine’s temperature.

However, the radiator could get clogged by debris and dirt. This article will answer questions like, can a clogged radiator cause overheating? We will also examine the symptoms of the clogged radiator and how to fix the problem.

radiator overheating no leaks

Can A Clogged Radiator Cause Overheating?

A clogged radiator can cause the engine to overheat because the dirt in the radiator will not allow the proper flow of coolants.

The engine relies mainly on the cooling system to regulate itself. The engine cooling system encompasses the cooling radiator, thermostat, cooling pump, and engine fan, among others.

Furthermore, the radiator plays a significant role in cooling, as it is meant to supply the engine with coolant that collects heat from each part. A radiator clogged up is caused by dirt or other contaminants from using old coolants. As a result, heat builds up, causing severe damage to engine parts.

Also, the accumulated heat in the engine is transferred to other parts of the vehicle, like the transmission system and radiator hoses, causing further damage.

We recommend regularly changing your coolant to prevent clogging and other issues with your cooling system.

Symptoms of a Clogged Radiator

Many clogged radiator symptoms are straight forward to notice and can reduce any vehicle’s reliability and driving condition. Some of these symptoms include the following.

1. Damaged radiator cooling fin

The radiator or cooling fin is a very fragile part of the radiator. When the radiator gets clogged, foreign material can easily enter the front. The foreign material can cause the fin to be bent or damaged.

Once the fin is damaged, it could restrict the airflow, which plays a significant role in ensuring the heat from the coolant is transferred to the airstream.

2. Leaking coolants

Coolant blockage in engineor the radiator could corrode parts of the radiator, causing leaks. These leaks can be visible on the ground, and in some cases, they could be very significant in quantity, depending on the size of the damage on the hose.

Corroded cooling fins, caused by clogs, are a leading cause of these leaks. Small holes or cracks are created when the fin is corroded, leading to leaks.  

3. Changed in coolant color, smell, and viscosity

Another sign of a clogged radiator is a coolant that changes color, odor and viscosity. Once you notice that your coolant color has changed, it means that coolants have been contaminated and are no longer usable.

You must regularly check your coolants during your period of maintenance. Please look at the coolant; it should be either light green or yellow. There are other colors that the coolants come from. However, if you observe that the coolant is now brownish and comes with an odor, it must be changed immediately.

Over time, external materials could get into the coolant and cause a reaction. When this happens, the coolant loses its unique properties and becomes ineffective. 

4. Damaged gasket head

A clogged radiator will indeed cause the engine to overheat. At this point, the engine is not receiving the needed coolants. When the engine overheats, parts of the engine, like the gasket head, are affected.

In the case of prolonged engine overheating, severe damage is caused to the gasket head, causing either a leak, blown head or cracked cylinder head.

5. Passenger heater not working

Another part of the vehicle that will also be affected by a clogged radiator is the heater. The passenger-side heater relies on the hot coolants passing through the heater core to create the heat needed.

Once you have a clogged radiator, there is a stop or limitation to coolant movement. Coolants will not pass through the heater core and will not work.

6. Water pump work inadequately

A major cause of clogged radiators is a contaminated coolant. When the coolants are contaminated, it could damage the water pump. The coolant loses most of its properties, making it more corrosive and less lubricative. It makes the fluid particularly dangerous to the water pump and can corrode or rust parts.

7. High reading temperature gauge

A common occurrence that will happen to the engine is that the temperature gauge will also be high when driving. It shows that the engine is getting overheated due to the lack of coolant circulation caused by the clogged radiator.

How to Fix a Clogged Radiator

Now that we understand the symptoms of a clogged radiator, and can most likely recognize when we have a clogged filter. The next thing is how we can have a clogged radiator fix.

To fix a clogged radiator, you must get an unclog radiator by draining out the old coolant. Below is how to unclog radiator through some easy-to-follow steps.


1. Park your vehicle in a comfortable area where you can perform the drain.

2. Place a drain pan or any receptacle to collect the coolants.

3. Go to settings control and turn the radiator’s temperature control to the hottest.

4. Find the pressure cap, usually at the radiator’s top. You can check your vehicle’s manual to locate the manual properly.

5. Twist off, remove the pressure cap, and drain the fluid completely.

6. Seal up the old coolant properly and ensure no spillage.

7. Cover the plugged radiator pressure cap correctly and refill it with new coolant.

8. You can flush the radiator system if you want to. 

Will Flushing Radiator Stop Overheating?

Flushing your radiator will stop overheating. Flushing the radiator will help you eliminate any blockages or clogs in the system. It allows the radiator to have a better coolant flow to the engine.

Flushing the radiator involves using a concoction of chemicals to clean the radiator. First, you will have to drain the vehicle of all old coolants. Then you run the chemical through the radiator using a hose.

Once the chemical runs through the radiator, it carries all foreign materials and other objects that could be causing blockages. Once the flush is done, the engine will no longer overheat because the system has a better circulation of coolants.


A clogged radiator hose or any other part of the radiator will result in overheating. You must take the necessary steps to prevent this by changing the cooling at the expected interval. You also need always to check the condition of the fluid.

Akindayini Temiloluwa

I am Akindayini Temiloluwa, an automotive expert writer and car enthusiast. I have over three years of experience in the automotive writing niche and have completed over 300 pieces of content from 50 projects. I have vast knowledge and skill in vehicle repairing, all mechanical work, car upgrades and maintenance. My goal as an automotive content writer is to simplify the most challenging concepts for my readers, help them self-diagnose what may be wrong with their vehicles and offer real value for their time.

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