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How to Bleed a Car Radiator: A DIY Guide

How to Bleed a Car Radiator: A DIY Guide

How to Bleed a Car Radiator

If you are wondering how to bleed a car radiator effectively, we have got you covered. It is essential to bleed the air out of the car’s radiator from time to time. Air pockets, or hot spots, tend to be dangerous as they can overheat, warp, or even crack any part of the engine.

Hot spots are nothing more than just trapped air bubbles or pockets that are present inside the cooling system passages, and these prevent the coolant from carrying the heat from these areas. As a result, it causes the engine to overheat, and the corrosion begins to settle in.

What is a Car Radiator?

When we talk about radiators, we often think about the ones in our homes. However, these radiators and the ones in our car are very different from each other. The radiator in your home is meant to keep the room warm, while the car radiator is meant to do the exact opposite—to keep your engine cool.

The car’s engine can seriously heat up to the point where it can literally melt metal. If it does happen in your car, there would be a catastrophic failure in the engine and would cost you a fortune to fix. These high temperatures occur due to friction between the parts that move.

You can minimize this friction with adequate motor oil that basically works as a lubricant. However, this is not enough to keep the car from seriously heating up. This is where the radiator comes in to do its job.

This engine coolant goes inside through the engine and then comes out from the other side and then goes into the radiator. It is designed in a manner to have a very large surface area to let all the heat dissipate. Some radiators even have fans that work in bringing in outside cooler air inside the car to help the radiator with its process.

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The car’s grill is designed for this purpose too. The cool outside air and the radiator cooling the coolant temperature makes the mixture cool enough to get back inside the engine and restart the process.

When the radiator does not work properly, or there is lack of coolant in the car, this could become a serious problem. The engine will get hotter until it blows a piston. Hence, it is crucial to check the radiator, oil levels, coolant, and so on a regular basis.

How to Bleed a Car Radiator

There are three methods you can use in order to bleed a radiator. These include:

  • Opening The Bleeder Valves

Certain vehicles will have a radiator bleeder valve, which will be located either at the front or at the top of the radiator. This valve is specifically made for bleeding the air off that got trapped in the radiator’s upper portion.

  • Elevating The Car

Another way to bleed the radiator is to simply put a jack in the front of the car and raise it from the front. As this lifts the vehicle, it will also lift your radiator up to the point that it will be higher than the rest of the cooling system.

What this does is that it forces the air pockets closed and allows the air bubbles to dissipate into the surrounding. However, when you opt to elevate your vehicle, you must ensure that the cap of the radiator or the reservoir tank is loose. This will help speed up the whole process of bleeding the radiator.

  • Turning On the Car with the Radiator Cap Off
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Another simple way to bleed the radiator is by simply removing the cap of the radiator, and then turning on your engine. Once you do that, leave the car on and running until you see it reach the normal temperature. This whole process would take between 15 and 20 minutes.

Allowing this much time means that you are allowing the car to generate the necessary heat enough to push out the trapped air bubbles or pockets inside the cooling system. You may find it necessary to add additional coolant as well since the air pockets can inflate the levels of the coolant artificially.

Flushing a Radiator

When you flush a radiator, it will not only refresh the coolant within, but it will also help in prolonging the life of the radiator by getting rid of all the debris that gets built up over time. This process is quite easy to learn and should not take more than an hour to do it.

To flush the radiator, you will need a pair of pliers, a drain pan, a garden hose, and most importantly, a fresh coolant.

Step 1 – Prep

Prepare the radiator by placing the pan under the car to catch hold of the old coolant. By removing the cap from the drain and the radiator, then the coolant will pour out.

Step 2 – Flush

Put the hose inside the top opening and turn the water on to a light flow. The radiator will get filled with water and will simultaneously flow out of the bottom drain. With the car off, it will flush only the radiator, with the car running, it will flush the whole cooling system.

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When the water coming from the bottom drain is clean, then that indicates that the radiator has bled fully. Remove the hose and replace with plug.

Step 3 – Replace

Replace the coolant slowly to avoid any air from building up. You can park the car on a slight upwards slope too if you think that would help you. When the coolant becomes visible in the radiator, switch the engine on.

The coolant will circulate as the engine warms up. Add more slowly until it is full. On a side note, most manufacturers recommend that a mix of 50:50 of coolant and water until the radiator gets full.

Step 4 – Fill and Check

Fill in the overflow (reservoir) tank with coolant as well. Keeping it full will help in removing the air bubbles inside. Drive your car for some time to warm the engine up. Turn the heater on and run for a few minutes. Stop the car and let it cool down again. Check the level of fluid one more time. You can add more coolant to top it off if you think it’s necessary.

Final Words

In conclusion, we hope this DIY guide has proven to be useful in understanding how to bleed a car radiator in the most effective and easiest way. After all, it is clearly a simple process that you won’t need to visit a mechanic for. Ensure you do it often so that you never give the engine a reason to overheat and cause damage.