Do You Need a New Radiator in Your Kia?

Your Kia Optima's cooling system is essential to keeping it running as it should, and almost no part in that system is as important as the radiator. Your car's radiator holds your coolant, allows it to release the heat it draws away from the engine and then allows it to be reintroduced to the engine. Here's everything you need to know about the function and maintenance of your Kia Optima's radiator.

How Does a Radiator Work?

The water or coolant that is pushed through your engine by the water pump draws heat from the engine block and its components. In order for the cooling system to be effective, however, that heat has to be released somewhere away from the engine. The radiator makes this possible by offering a high-surface area container from which heat can be released. This process is called heat radiation, hence the term "radiator."

If you look carefully at your radiator, you'll notice that it is covered in tiny metal flaps. As opposed to a flat surface, these flaps greatly increase the surface area of your radiator. More surface area means that more heat will be transferred out of the water and into the air around the radiator in the same amount of time.

Your car's radiator is positioned at the very front of your vehicle. Here, the air being forced around it as you drive your Optima can pick up the heat being radiated outward from the radiator and carry it away. This is the basic process by which heat is removed from your engine.

What Makes Radiators Wear Out?

Under normal conditions, radiators have very long life spans. Since they have no internal moving parts, the normal wear and tear of mechanical working affects them very little. However, radiators can still be affected by many things. One of the most common problems that can cause a radiator to give out is physical damage. In order to make it easy for heat energy to transfer out of the water inside the radiator to the outer surface of it, radiators are made of fairly thin material. This makes them prone to physical damage. Once a radiator is punctured, it can no longer do its job.

Usually, this kind of damage is due to road debris, such as loose asphalt, getting thrown up against the radiator. This problem is worst in places with hot summers and cold winters, which cause asphalt to crack much more easily. Here in Bradford, Connecticut, we don't have this kind of road damage to the same degree other parts of the country do, but loose gravel or asphalt on the road can still cause radiator punctures from time to time.

Another problem that often comes up is dirt, grime and debris building up inside the radiator. Inside a radiator, water is conveyed through tubes that allow it to transfer heat to the outside. If these tubes become clogged up, your radiator will become less effective at cooling and your engine will gradually begin running hotter as a result.

Proper Radiator Maintenance

One of the common parts of car maintenance that many people forget or neglect is radiator maintenance. Everyone knows you need to replace your coolant from time to time, but it's less common knowledge that, in order to fully get rid of grime and buildup, your radiator needs to be flushed on occasion. Generally, it's a good idea to have your radiator flushed every 20-30,000 miles. In flushing, water will be run through the radiator during a coolant change to remove excess buildup and dirt in the internal tubes.

How to Drain and Flush Your Kia Optima's Radiator

If you want to drain your own radiator, it's actually a fairly simple process. At the bottom of your radiator, there's a green drain plug that can be accessed after the removal of a plastic bottom cover. Once you have access to that plug, you can simply remove it and allow the coolant to drain into a pan or other container. Be sure to let your radiator drain completely before replacing the drain plug and refilling it with coolant.

If you want to flush your radiator at the same time as draining it, the process is still much the same. Drain your radiator as described above and replace the drain plug, but this time, fill your radiator up with water from a garden hose. Turn your Optima on and run it for a few minutes, then turn it off again, let it cool down and drain the water. Repeat this process a few times to get all of the grime out of your radiator. If you want even better results, there are also flushing chemicals you can buy that will help to remove even more of the radiator's internal buildup.

Knowing When You Need a New Radiator

If your radiator becomes damaged, chances are you'll be able to tell from a puddle of coolant forming underneath your car. Some radiator leaks are slow and small, draining your radiator out over several days, while others are large enough to simply drain your radiator all at once. What type you will have depends on the way in which the radiator is punctured.

If you do find that you have even a small radiator leak, don't wait to replace your radiator. A small leak can blow out into a much larger one at any time. If your radiator suddenly has little to no coolant in it, your engine will be completely unable to cool itself down. If allowed to run like that, the engine will rapidly overheat, potentially causing catastrophic damage.

When replacing your radiator, be sure you are getting a new OEM unit to replace it with. Radiators sold by aftermarket manufacturers may be able to cool your car down, but they will not be specifically configured to fit the Kia Optima as well as an OEM radiator will.


If you need a replacement for your Optima's radiator, come to, a Bradford, Connecticut, based parts dealer specializing in all things Kia. No matter what parts you need, we've got the selection you're looking for to keep your Kia Optima in great driving condition.