What is a car radiator?

7 minute read Published on Mar 29, 2024 by BrokerLink Communications

An auto mechanic holding a car radiator in a repair shop

Understanding how your car works is essential, especially if you want to prevent problems down the line. Thankfully, the team at BrokerLink is here to shed some light on an important component of your car: the car radiator. Continue reading to learn more about how car radiators work and how the right car insurance policy can help you pay for your radiator to be repaired or replaced should something go wrong.

Car radiator definition

Let’s begin by explaining what a car radiator is. In the most basic terms, a car radiator is the part of your car responsible for keeping things cool. Its purpose is to regulate your vehicle's engine temperature to prevent it from overheating.

How do car radiators work?

To answer this question, let’s first explain why it’s crucial for a car’s engine temperature to be regulated. The reality is that a car engine works hard, and as a result of this, it can become hot. In order to run, your engine must burn through fuel, producing energy in the process. The power that your engine creates can generate a lot of heat. That’s where the radiator comes in.

While a certain amount of heat is average, if your engine overheats, this can spell trouble. An overheated engine can cause severe damage to your car that could cost thousands of dollars or more to fix. Thankfully, if your car radiator works as it should, it will help remove excess heat from the engine.

A radiator can remove heat through a multi-step process involving a fan, a thermostat, hoses, and a liquid coolant. More specifically, the liquid coolant enters the hoses via the radiator. From there, it travels to the engine to absorb the extra heat before returning to the radiator. Once back in the radiator, thin metal fins disseminate the heat from the coolant to the outside. This cool outside air then flows into the radiator via the grille on the front of the car.

Then, when your vehicle is stationary, such as when it’s stopped at an intersection or idling, the fan will blow air to decrease the coolant’s temperature further and blow the hot air from the car to the outside in the process. Finally, the cycle starts again, with the cooled-off coolant passing through the radiator and travelling into the engine again. As you can see, the radiator’s primary design is to regulate the engine’s temperature.

Parts of a car radiator

A car radiator consists of four main components: the core, the pressure cap, the outlet and inlet tanks, and the radiator hoses. To fully understand how a radiator works, we explain each of these parts and how they function:


The core is the most significant part of the car radiator and the main component of it. Think of the core as a metal bowl featuring rows of thin metal cooling fins. These fins help to vent and cool the air. The core is the location where the warmed coolant, after having flowed through the engine, releases its heat and cools off. This portion of the process must be done before the coolant can return to the engine to continue the cycle.

Pressure cap

The pressure cap is the piece of the radiator that seals the cooling system, helping to make sure that it remains pressurized. Why is pressure so important? Pressure is part of what allows the radiator to operate as it should, as it prevents the coolant from boiling.

Inlet and outlet tanks

Finally, the inlet and outlet tanks are the tanks through which the coolant flows in and out of the radiator. They are located in the radiator head. These tanks are responsible for housing the coolant when it is scorching. When the liquid leaves the engine, it first ends up in the inlet tank, which cools off and then travels to the outlet tank and back to the engine.

Radiator hoses

Finally, the radiator hoses are used to connect the inlet and outlet tanks to the radiator and the car engine. The coolant moves through these hoses as it travels in and out of the engine.

Other parts of your engine’s cooling system

While not directly part of the car radiator, a few other vital parts of the engine’s cooling system are worth mentioning. For example, both the water pump and thermostat work alongside various parts of your radiator to ensure the engine remains cool and operates efficiently.

First, the thermostat aids the radiator in regulating the engine’s temperature. It detects the engine's temperature and opens when it reaches a specific temperature to allow an influx in the amount of coolant that enters the engine. Alternatively, the thermostat will close and remain closed if the engine is at the optimal temperature.

Second, the water pump is the part of the engine’s cooling system that is responsible for pushing the coolant through the system. It is usually pushed through the system via an engine drive belt that then turns on the pump. From there, spinning blades push liquid through the cooling system as needed, and then the gaskets and seals keep the coolant contained.

Signs of a problem with your car radiator

Given the critical role that a car radiator plays in the effective running of your engine and, thus, your car, it is vital to know what the signs of a problem are. To help you identify a problem with your car radiator, continue reading for a list of signs and symptoms of a car radiator failure:

Coolant leaking underneath your vehicle

If you notice coolant leaking from your car, especially from underneath your vehicle, onto the ground, this could be a sign of a crack or leak in your car radiator. You are most likely to notice this while you are parked or as you back out of your driveway. If you see this alongside low coolant levels, then you could have a leak on your hands. Please note that coolant typically looks green in colour.

Discoloured coolant

Another sign of a problem with your car radiator is if you notice that your coolant has become discoloured. Coolant should be green or yellow in colour and have a thin consistency. However, if your radiator has started to fail due to rust or caught debris, it can contaminate the fluid, turning it a darker colour and making it thicker.

So, ultimately, if you think that your coolant looks thick, like sludge, or rusty in colour, you should have your radiator looked at. Speaking of rust, be sure to check your cooling system regularly for evidence of rust, as rust can wreak havoc on a vehicle. This is an essential summer and winter car maintenance tip.

An overheated engine

If you notice that your engine is overheating on a regular basis, this is a telltale sign that your car radiator isn’t functioning as it should be. A clear symptom of engine overheating is the smell of smoking coming from your car or seeing smoke emanating from the hood of your car.

If you notice a problem with your car’s radiator, contact your mechanic or local car dealership immediately. The sooner you discover the problem, the quicker your vehicle can be fixed. Depending on the cause of the problem, your car insurance policy might cover you for the cost of repairs. For example, if the cause of the damage was an accident in which the other driver was at fault, then third-party liability car insurance might pay for the necessary repairs.

How to maintain your car’s radiator to prevent problems

If you want to avoid a problem with your car radiator, follow these preventative tips:

Replace your radiator hoses regularly

First, make sure that you replace your car’s radiator hoses on a regular basis. Most experts recommend replacing them every three years or 36,000 miles of driving - whichever comes first. Generally speaking, you should not drive more than 50,000 miles without changing your radiator hoses.

Inspect coolant levels

Our second tip is to inspect the coolant levels in your radiator. Fluid levels can drop for several reasons, and driving with levels that are too low can cause overheating. So pay close attention to coolant levels, as noticing a fast drop in levels can also signal a leak, and it’s always best to catch these early.

Flush your coolant frequently

Finally, take care to flush your coolant every 25,000 miles. The reality is that contaminants can build up, leak into the engine and cause problems. Flushing out your coolant will remove any impurities in the radiator and hoses. Doing so can also prevent rusting.

Contact BrokerLink today

If you have other questions about how your car's radiator works and how you can protect it, contact BrokerLink today. As insurance experts, we can explain what types of auto insurance are available to you and how they might be able to help you cover the cost of repairing or replacing your car radiator if necessary. A few of these types include:

If you’re ready to purchase car insurance, contact BrokerLink for an insurance quote. As a full-service brokerage, we can also help you keep your car safe in other ways. For instance, one of our licensed insurance advisors can provide tips for driving on icy roads, explain the steps to take if you’re trapped in a vehicle in the snow, and explain the importance of snow tires on winter drives. Contact BrokerLink today to learn more about car radiators and auto insurance in your area.

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