What is a car radiator?
Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics.
A radiator is always a source of heat to its environment, although this may be for either the purpose of heating this environment or for cooling the fluid or coolant supplied to it, as for automotive engine cooling and HVAC dry cooling towers. Despite the name, most radiators transfer the bulk of their heat via convection instead of thermal radiation.
Engines create a lot of heat in their operations – they’re powered off of miniature explosives! To prevent your engine from overheating, your car pumps coolant through your engine – the fluid that receives heat and carries it away from the engine block.
The coolant takes the heat generated by your engine and moves it to your radiator, which blows air across the liquid – cooling it down and exchanging heat with the air outside your car.
The radiator works bypassing your coolant through thin metal fins, which allow the heat to flow to the air outside your car much more easily. Sometimes, there is a fan that blows air across the radiator in order to carry the hot air out of your car.
Radiators come in many different shapes, sizes, and designs, but their primary function remains the same. In essence – a radiator cools the coolant, which then cools your engine.
Parts of a Radiator
- Core: The core is the largest part of the radiator and provides its primary function. It consists of a large metal block with small metal fins that allow the coolant to vent heat to the air surrounding the radiator (this air is expelled in your grill at the front of your car.) There are many types of cores, for example, one-core, two-core, or even three-core radiators.
- Pressure cap: Your car’s coolant system is continually under pressure. This is because it allows the coolant to become much hotter without boiling than it would normally, which allows the system to be much more efficient. The pressure cap creates this pressure by using a spring to create pressures up to 20 PSI. It’s important not to remove the pressure cap while the coolant is hot, or you can cause serious burns.
- Outlet and Inlet Tanks: The inlet and outlet tanks help the radiator move coolant from the hot parts of your engine to the radiator.
- Transmission cooler: Your car likely uses the same coolant that your engine uses to cool your transmission. Transmission fluid moves through your engine through steel pipes, which are surrounded by coolant that conduct heat away from them. This coolant is also cooled within the radiator; as serious heat is generated through automatic transmission. Sometimes, there is a separate radiator to cool down your transmission fluid, if serious stress is generated by your transmission, but it is much more common to see a single radiator for both these functions.
Why is your radiator important?
A radiator is important because it is the chief way your engine vents heat during operation. A malfunctioning radiator may cause significant engine damage caused by overheating – in most cars you see the billowing smoke on the side of the road is actually caused by malfunctioning radiators!
The most common cause of radiator malfunction is physical damage, which warrants a replacement of one or all of its components. Radiator function can be impaired by expired coolant or lacking coolant levels, which can be fixed via a coolant flush.
How does a car radiator work?
An engine needs to burn fuel to run, a process that naturally produces an immense amount of heat. The engine, therefore, needs to be cooled as much as possible so that the pistons do not break down and destroy the entire system.
This is where the radiator, which is part of the engine’s cooling system, comes in.
How your car radiator cools the engine
- The coolant in an engine is passed through tubes inside the radiator, where heat it has absorbed from the engine is dissipated into the atmosphere, before the coolant returns to the engine.
- Coolant enters the pipes in an overheated state, causing it to become highly pressurized (aided by turbulence inside the radiator pipes).
- This causes the radiator cap to open at a predetermined pressure point.
- The heat is released, allowing any excess coolant to escape into an overflow tank attached to the side of the radiator.
- That coolant is then returned to the radiator when its temperature has sufficiently lowered.
Radiator and cooling systems vary slightly from model to model (especially in older cars versus newer models), but this is the process that the majority of systems employ.
Why do car radiators fail?
The main reason for radiator failure is a coolant leak, which can lead to the cooling system failing.
If the coolant has not been checked or topped up properly, the radiator, hoses, and hose connections will become clogged and begin to rust. Over time, such corrosion will cause small holes or ‘pinhole leaks’ to develop in the car radiator.
This will result in engine coolant loss and a need for car radiator repair – or even the complete replacement of your radiator.
How Much to Fix a Radiator?
Radiator Replacement Costs
Replacing a radiator or fixing a fan can cost anywhere between 100 and 900 dollars if you’re taking your car to the shop. A typical replacement, however, is often around 400 dollars. How much it costs to fix a radiator varies greatly from vehicle to vehicle and depends on how you choose to get it fixed.
Many late model cars from the 70s, 80s, and earlier had radiators made entirely of metal, often copper or brass. These radiators could actually be repaired. If it sprang a leak, you could fix the leak and keep using the same radiator.
Newer vehicles use radiators that are built from an aluminum core (the part with the tubes and fins) and plastic end tanks (the black parts on the sides or top and bottom of your radiator where the hoses connect). These are very difficult to repair and almost always have to be replaced with a new radiator.
If you’re replacing your radiator at home, costs will be on the lower end (100 to 300 dollars). However, if you are going to a garage, labor costs can bring your price all the way up to six or 700 dollars.
Why Is Replacing a Radiator So Expensive?
Radiator replacement is partly expensive because you will need to drain and refill your cooling system. Due to the size of most vehicle’s cooling systems, there can be a significant expense just in antifreeze. Using a universal type of antifreeze is a good way to save money while still getting your car back on the road.
Purchasing the antifreeze in concentrated form is always less expensive than using pre-diluted coolant. Just make sure you use the product that is right for your vehicle! If you have questions on which type or color of antifreeze to use, check out our article about which antifreeze color you should use.
Another thing that adds to the radiator replacement cost for your vehicle is the coolant disposal fee. Engine coolant is an environmental hazard and needs to be disposed of carefully. The additives in antifreeze are hazardous to the environment as they can be extremely deadly when ingested by any living organism.
If you hire a repair shop to replace your radiator, they have to pay an extra fee to dispose of the antifreeze they remove from your vehicle. Even if you chose to replace your own radiator, you may have to pay a fee at your local landfill or recycling center.