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How To Flush A Radiator: A DIY & Best Tips Guide

how to flush a radiator How To Flush A Radiator: A DIY & Best Tips Guide

Imagine the following situation – it is summertime and you and your beloved family are heading to a nearby ocean resort to spend a wonderful 2 weeks there as your year vacation. The mood is high, the weather is amazing, the whole car is singing while you are driving on the highway and it seems like nothing could go wrong. Until you notice that alarming lamp on your car’s dashboard, saying that your engine is about to explode. And yes, that is how little it takes for your cheerful mood to be ruined. And if you get back and think over why you hadn’t done that little step you had to do in order to ensure that your car’s cooling system will be able to handle the extreme engine heat in that warm summer weather, you will possibly feel way more annoyed.

But look on the bright side – this will be an important lesson learned and next time you will be more cautious.

In this guide you will find out more about the vehicle cooling system and will learn how to handle one of the most important tasks, related to it – flushing the radiator DIY. After that you will be able to run a periodical check on the fluid’s condition and the radiator components in order to avoid similar unpleasant situations like the one listed above.

Radiators and vehicle cooling systems

Having a properly functioning radiator is essential for the overall performance of your vehicle and keeping its engine from overheating. Basically, a car cooling system works as a coolant liquid, heated by the running engine, flows through the radiator.

The role of the radiator is to ensure the continuous cooling of that liquid by rapid heat exchange. With the course of time, that cooling liquid becomes less effective as sludge and debris are slowly building up inside the radiator unit. When the system’s efficiency is reduced, the performance of your car’s engine can be significantly harmed, which will also lead to an increased fuel consumption.

That is why flushing a car’s radiator is so important. Experts suggest to do it once every 2 – 3 years. That way you will ensure the smooth operation of your car and the good performance of its engine. A well-maintained cooling system is projected to serve you for more than 15 years, which in most cases is more than the period that you will hold your car.

How to flush your radiator DIY

Maintaining the good condition of your car’s cooling system does not always require professional help. Just the opposite, when it comes to flushing your radiator in order to keep it clean and optimize its cooling function, it can all be handled DIY. In order to make sure that everything goes smoothly and you achieve your final goal easily, you should focus on going through the following steps:

1) Getting the needed tools

First of all, let’s find out what you will need to handle the work smoothly. A radiator flush requires from you to have:

  • Head screwdriver or wrench
  • Cloth rag
  • Radiator flush solution
  • Coolant product
  • Funnel
  • Used coolant receptacle

Make sure to get all these things before you start doing the job. There is nothing more annoying than finding out that you have missed to get some of the needed tools and should somehow reach the auto store when you have already drained your radiator.

2) Preparation

The starting point is to make sure that your engine has cooled entirely. That is why many car owners prefer to do that in the morning, when they hadn’t used their cars for more than 8 hours at least. But if you are in the middle of the day and you decide to flush the radiator, you should bear in mind that car engines usually take up to 2 hours to cool entirely when the air temperature is in normal levels. In case you are doing that on a warm summer day, you should know that the engine may take up to 5 hours to reach a condition in which you can work. This is vitally important because of the fact that the car cooling system works that are performed when the engine is still hot, can be dangerous for your health as you can get your hands and face burned.

3) Lift the car from the front (optional)

It is not always required to do this, but jacking up the front side of your car will make it easier for you to work underneath the radiator. It will also help you eliminate the air bubbles from the coolant after the radiator is flushed.

4) Find the exact location of the radiator’s components

If you are familiar with the position of every element under your front hood, then you may skip this point. Otherwise, look around to find the radiator at first. It is almost always located near the engine in the front part of the car. A good thing to do here is to carefully clean all the metal slats that are located on the front and the back side of the radiator with soapy water and a soft brush. That way you will allow the air to flow seamlessly.

Make sure to brush only in the direction of the radiator and not against it (otherwise you risk damaging it). After you are finished with this, localize the radiator’s drain plug. It may be placed anywhere near the bottom of the radiator. If you have troubles finding it, bear in mind that the drain plug is usually a simple drain valve, screw or bolt plug. After you find the drain plug, make sure to place the receptacle beneath it, before you open it up.

5) Drain the radiator

First of all, you should check the user’s manual in order to find how much coolant is there in the system. This is very important because the capacities of different vehicles often vary. For example, some cars hold only 6 quarts, while others can hold up to 18 quarts. Next, make sure to put some protective gloves on your hands, because of the toxicity of the radiator’s coolant. Then open the plug and drain the liquid into the receptacle. Once you are done, put a lid on your drainage pan and then set aside. The drained coolant can be taken to a mechanic or auto shop in order to be recycled.

The initial draining of the radiator normally will remove approximately 40% – 50% of the coolant. After you are finished with it, make sure to fill the system with water (or with water and radiator flush cleaner). Then warm up the engine and start the heating unit by setting it to the maximum temperature. Leave it working for 10 minutes and after that, stop the engine and let it cool entirely. Then drain the radiator and fill it once again. Repeat this procedure at least 2 times.

6) Fill the radiator

Now that you are almost ready with the radiator flush and it is time to refill it with new coolant. Make sure to use only coolant that is suitable for the specifications of your car’s cooling system. After you are ready, fill the radiator with a mixture of coolant and distilled water (1:1).

7) Check the levels

Because of the air bubbles that may force their way out, you may need to add a little bit more coolant. To find out, take off the cap and start the engine. Once again, start the heating unit and leave it that way for 10 – 15 minutes. By doing that, you will make way for the air bubbles to escape, which will make room for additional coolant.

Now that you are done with it, without the need of visiting a mechanic – for just a few hours, you have a flushed radiator that operates like new.

Useful tips

Flushing a radiator is a not so challenging task. Yet, it is not just a matter of draining and filling of antifreeze. That is why, there are some useful tips that can help you maintain the good condition of your car for the long-term. Take a look on the following advice in order to go through the process easier and faster:

On corrosion. Car engines nowadays are made from various aluminum elements – from water pumps, manifolds and cylinder heads to engine block and etc. Even the major heat exchanging components (the radiator and the heater) are made from aluminum. While having many important advantages as a material, the aluminum is prone to corrosion. And if it is not rightly protected, it can lead to the need of making significant investments for new parts or repairs of the existing ones.

Different antifreezes have different periods for ensuring the right corrosion protection. For example, experts suggest to use the green and the red ones for no more than 2 years. Orange antifreeze, on the other hand, is a pretty new invention and it offers longer life and protection. But bear in mind that if your car comes with green or red antifreeze, it is not advisable to instantaneously switch to an orange one. That switch usually needs some initial preparation and the best thing to do here is to consult a professional auto repair specialist. No matter what kind of antifreeze you use, you simply cannot escape from the need to flush your radiator once every 2 – 3 years.

On the condition of the radiator. When you have decided to flush your radiator, it is a very suitable moment to check its condition also. But how to do it if you are not a professional? Of course you won’t be able to find any in-depth problems, but you can easily notice if there are some suspicious characteristics that can cause them in the future. For example, when you open your hood, make sure to look for large patches of corrosion, rust or leaky hoses (potentially pipes also). And if you can smell antifreeze every once in a while, that means you may have a leak in the radiator or some of its elements. Even if these problems may seem hard to solve for you, you can visit the car shop with a ready-made explanation and have it solved for no more than an hour.

On the condition of the radiator’s elements. One of the most widely spread reasons for radiator problems is actually a very easily fixable one. The radiator cap is just a small element that serves to keep it under pressure. It consists of a rubber seal and metal top with a spring coil between them. The tension that is formed between the spring and the seal helps the radiator to maintain the needed pressure. If any of these tiny elements get harmed or worn out, a new cap is much needed. But don’t worry, radiator caps usually cost few dollars and can be replaced for a few seconds.

Except the cap, you should also check the two hoses coming out from the radiator every once in a while. The top one serves for the hot coolant to flow into the radiator, while the lower one is intended for the cooled coolant to get into the engine (that happens through a coolant pump). Make sure to check whether they are both working properly and there are no visible leaks or clogs.

Video Resource

The procedure of flushing a radiator is pretty much a standard one and should not cause you any problems. Doing that once every two – three years will help you maintain a better performance of your engine and will preserve you from facing any unexpected road emergencies. Yet, if you feel that it seems hard-to-handle, ask a friend to help you or better visit an auto repair expert. By the first time you perform that process by yourself or even witness it while someone else is doing it, you will feel comfortable that the next time, that antifreeze will be drained and refiled entirely by you!