How to Flush a Radiator (& 4 Common Signs that You Need New Coolant!)

A car is one of our most important possessions. Like other assets, it requires proper maintenance to run smoothly. Maintenance routines such as regularly checking up on your engine’s air filter and rotating your vehicle’s tires are necessary. They extend your car’s lifespan and ensure your safety while on the road. One aspect that some car owners tend to overlook is the radiator fluid. This coolant is tasked to keep your engine running steadily under safe temperatures. It prevents your car from overheating, which could lead to even worse troubles. Keeping the right amount inside your car is just as important as gassing up your vehicle.

This article will discuss everything you need to know about radiator fluid, such as tips when adding coolant. We’ll go through how to flush a radiator and signs that your vehicle needs a flush.

Make sure to check out our articles on Thermo King fault codes and Hibiscus trees. Yes, we cover many different topics on Atlantic Aspiration!

coolant being added to car
What does radiator fluid do?

Also known as antifreeze, the radiator fluid is responsible for cooling the internal combustion engine so your vehicle can run smoothly. It prevents your engine from overheating when the weather is too hot and avoids freezing when it is too cold. Without it, the risk of damaging your car and car parts is severe. Antifreeze is generally a combination of propylene glycol or ethylene and water, with a 50:50 ratio. Experts also recommend other base types, discussing those in the succeeding subsections.

So, how does radiator fluid work? The liquid circulates through the engine block and gathers heat from there. The heated fluid passes through a rubber hose and goes through the radiator. The liquid cools via the air stream through the thin tubes.

If you are driving on the road and your coolant malfunctions or runs out, this could cause damage to your vehicle’s engine parts. It’s particularly bad for the parts of those prone to overheating. These include the head gasket and water pump. The piston timing and cylinder head are also at risk. You can always have them repaired. You may have to spend a huge amount of money on something that could have been easily avoided through regular maintenance check-ups.

Radiator fluid is just one of the many types of fluids that run inside your car. These types include engine oil, a lubricant that allows your car to run smoothly. Power steering fluid is responsible for lubricating the steering gear. Brake fluid is the one that adopts pressurized fluid for brake activation. Refrigerant is the fluid responsible for your vehicle’s A/C system. With all these types of fluids required to run inside your car, you may want to consider buying a waste oil heater. Make better use of old oil instead of disposing of it completely.

How long does coolant last in a car, & how often should you flush it?

Now that you know how it works and its importance in maintaining your car, the next question begs how long coolants last in a vehicle. Unfortunately, there is not a one-size-fits-all answer to that question. Some say you have to change it every three years, while others believe it is best to flush the radiator fluid annually. There is a consensus that if your car is new and has only achieved less than 10,000 miles, there is no need to perform a flush.

Beyond this, there are different factors to consider when determining whether it is time to flush your car radiator’s fluid. Generally, car makers recommend changing yours every 30,000 miles. However, your driving habits also play a role in knowing the frequency of your radiator’s fluid changes. For example, suppose you frequently use your vehicle under extremely hot conditions. You may have to flush the radiator fluid every 12,000 to 15,000 miles, or about once a year. Your brand and model are other factors. Some Mercedes-Benz models need a fluid flush within a 30,000-mile interval, while others can last up to 120,000 miles.

Meanwhile, coolants on most Chevrolets last after every 150,000 miles regardless of driving habits. It is typically advised to flush it after 160,000 kilometers, or 100,000 miles for modern cars. In contrast, others may need a shorter mileage than this. You may want to consult your user manual or check with your vehicle manufacturer if you are still unsure when to change it.

Does antifreeze go bad in your car?

The lifespan of a concentrated antifreeze or coolant is indefinite. That is why you would not see an expiration date on the labels that have not been mixed with water. On the other hand, pre-mixed coolant may expire within 3 years from purchase. Maybe you have a leftover coolant solution after refilling your car’s system. Make sure to store them in a secure container so they can last for years. However, there are storage guidelines that you need to keep in mind.

First, use the original container when storing the leftover solution because its airtight lid helps keep contaminants at bay. Second, make sure to keep the containers away from children and pets as these liquids are toxic and poisonous. Lastly, always label the containers so as not to mix them up with other fluids in your garage.

But what happens when you have already added the antifreeze to your car’s cooling system? Does it start to expire right away? Once inside the system, it begins to degrade. Hence, experts recommend replacing or flushing it out at certain intervals. This depends on the vehicle’s model and driving conditions. It is advisable to check its quality inside your car every 50,000 miles.

Why it’s important
Smooth runningAvoids freezing
Prevents overheatingAvoid damage
radiator inside a car

What kind of coolant does my car need?

Just like when purchasing an engine-driven welder or a gasless MIG welder, buying coolant requires careful consideration. Ensure your money is well spent. There are two things to consider when buying it: type and base.

The two types are Type A, and Type B. Type A has an anti-boil and antifreeze component. It contains either propylene glycol or ethylene glycol to raise the boiling level while lowering the freezing point. Its inhibitor is used to protect your car’s engine from rust, cavitation, and corrosion. Unlike Type A, Type B does not have emulsions or antifreeze to accompany its inhibitor. It makes it only effective for preventing rust and corrosion. However, some variants may have anti-cavitation agents for better performance. Type B was very popular among vehicles launched before the 1980s.

Another factor to consider is the base. This can be classified into:

  • Inorganic acid technology
  • Organic acid technology
  • and hybrid organic technology

If you are shopping for coolants, you may notice that they come in various colors. This is because most manufacturers add dyes to differentiate one base from another. Organic acid technology typically comes in orange and dark green. You can also find it in bright red and blue. This base does not have phosphates or silicates, but it does have corrosion inhibitors to make the engine last longer. Models manufactured by Nissan and Toyota use this base. As do cars from General Motors and Honda. Got a Mitsubishi or a Volkswagen? You guessed it.

Meanwhile, inorganic acid technology is typically used on older cars. It’s particularly popular in those made between the 1920s and 1990s. This base covers the engine and radiator with corrosion inhibitors and silicates. It comes in bright green color and is advised to be flushed out every two years or about 30,000 miles. Another type of base to consider is hybrid organic acid technology. As the name implies, this base combines the previous two solutions and is recommended for newer models. It has silicates to prevent corrosion and additives to avoid rusting. It is available in turquoise, purple, yellow, blue, or pink. One popular example is the Prestone antifreeze, which helps prevent engine failure. This universal solution can be combined with another product without risking any damage. Many European- and Asian-made vehicles work great with this type. American-produced vehicles also work well with Prestone antifreeze, including pick-up trucks like the Dodge Ram.

A rule of thumb when deciding the right coolant for your car is to consult your dealer. They are best positioned to determine the right type specific to your model.

Signs that it’s about time for a flush

Imagine driving on the road when you noticed an odd smell from your hood that reminded you of maple syrup. Maybe you even heard some noise coming from your engine. Most likely than not, that is your coolant telling you that it needs to be flushed out. Here are four common indicators that your car needs a coolant flush.

Signs you need coolant.
Pancake-like smellOverheating
LeakingLevel emptying

The first telltale sign of a much-needed flush is the pancake-like smell rising from the hood. This is largely due to the sweet-smelling properties found in ethylene glycol. Overheating is also another sign to watch out for. Suppose your car overheats easily even when not frequently driving under hot temperatures. This is a sure sign that your coolant is no longer functioning properly. You need to consider going to your mechanic to have your car checked. The third hint that your cooling engine system is compromised is leaking. If you notice tracks of colored liquid where your vehicle is parked, consult a professional mechanic immediately. Make sure to have it inspected quickly.

If your coolant level empties earlier than it should, then there must be something wrong with your car. This is why it is important to regularly monitor your reservoir to avoid repeatedly topping up at shorter-than-recommended intervals. If you want to know how to check the level, check out the subsections below. While scrolling, you may also want to check out our complete guide on the best wide belt sanders.

How to flush a radiator’s coolant (aka how to bleed it)

radiator of a car

Now that you know the importance of a coolant system, learning how to flush it is next. Knowing when to do it depends on several factors, including mileage and model. Your driving habits will influence it as well. Flushing out the radiator coolant during the recommended time interval is also important. It prevents the build-up of debris and other unwanted contaminants.

Before starting to bleed your system, make sure that you have the following tools:

  • Drain pan or bucket that has a capacity of at least 15 liters
  • Distilled water
  • Radiator flush solution
  • Fresh coolant
  • Wrench or screwdriver
  • A pail of water or running faucet
  • Safety goggles

How to flush a radiator’s coolant (aka how to bleed it)

  1. Wear your safety goggles and park your car on a flat floor or surface.

    Make sure that the engine is cool. Skip to the next few paragraphs if you are unsure how long you should wait for the engine to cool down. Letting the engine sit for a while is important to prevent burns when opening the radiator cap. You also need to ensure that cats and children are out of sight since the coolant is highly poisonous. You may likewise consider a working area free from litter or away from distracting shrubs or vines.

  2. Place your bucket under the drain plug, allowing it to catch the fluid spills.

    Remove the radiator’s cap and the drain plug to bleed the system. It can be found at the bottom of the engine. This plug can come in the form of a petcock or screw. Once the drain is open, allow the fluid to flow until the container is empty.

  3. Put the drain plug back to its original position and properly dispose of the spills caught by the drain pan.

    You may want to purchase a large container similar to a fuel transfer tank. It should be one where you can put these waste spills to get rid of them later in an eco-friendly way.

  4. The next step involves the flush solution.

    Pour this solution via the open radiator cap and into the container. The radiator container must be filled in with water through your hose. Ensure that the water is about an inch below the radiator’s neck.

  5. Put the cap back in and tighten it.

    Go inside your car and start the engine, allowing it to run for about 10 minutes. The gear must be on neutral before starting this process.

  6. Turn off the engine and let it sit for some time to cool down.

  7. Turn to your drain plug.

    Open it, and let the solution flow out of it once more and into the newly replaced bucket under the radiator.

  8. Put the drain plug back in and tighten its cap as in the previous steps.

  9. Consult your user manual to know the capacity of your cooling system.

  10. Refill the radiator with a fresh engine coolant may require distilled water using a sterile solution. Check the solution’s label to be sure if it is already diluted.

    Once filled, close the radiator by tightening its cap and let your engine run for another 10 minutes. This will allow even distribution.

Flushing a radiator with vinegar

When checking your radiator, you may notice floating debris or bugs. Maybe there’s other gunk that can cause clogged drains and block airflow. If not addressed properly, this could lead to overheating. Thankfully, there is one household item that can help solve this.

Aside from pairing it with cucumbers, vinegar can also flush radiator fluid. It’s among the many other things that this versatile solution can do! Vinegar contains mild acetic acid that works safely enough with metals. But just like other solutions, you have to use this ingredient in moderation to avoid damaging your engine. Vinegar can also clean the main cooling system if calcium carbonate deposits. Since it often uses distilled water, the chance of having these unwanted contaminants is slim.

How long does it take for a car to cool down?

The exact time it takes a car to cool down depends on different factors. It includes the amount of engine coolant and the ambient temperature. The kind of material the engine block is made of will also influence it. On average, a car needs 1 to 2 hours after the engine is turned off to get to where you want it to be. If you plan to check your car’s coolant level, you may want to wait up to 5 hours. After the engine is off, the residual heat is still taking its sweet time to travel through the coolant.

While it is still hot, inspecting your engine can cause serious damage such as burns and scalds. Have patience and wait before opening the cap. It is a must. You can also check your car’s temperature gauge to see if it is safe to inspect your engine. This should be done with caution as it can sometimes give a false reading.

How much does my car hold?

Knowing your radiator’s capacity is one step closer to ensuring that your engine runs smoothly. Thankfully, this is a straightforward process you can do by yourself. The information needed should be available in your user manual. On average, a car has space for more than 2 gallons. You can also manually check your car’s capacity by flushing the fluid out of the radiator. Refill it with 1 quart of distilled water at a time. The water level should hit the piping of the expansion tank. After calculating the result, empty the radiator again and fill it with a coolant solution and water. You can refill the overflow tank to adjust the level.

How much should be in the overflow tank?

A radiator overflow tank gathers the expanding antifreeze or coolant heated by the engine. Afterward, it recycles and passes it back through the system once the heat level eases. The function of the overflow tank is connected with that of the cap. Both help in engine protection and avoid overflowing that could lead to loss. Cars that do not have a radiator overflow tank are more prone to rust. An overflow tank must be filled with just the right volume to avoid leaks.

How to check the level

Regularly monitoring the coolant level is important in ensuring that your car runs smoothly. It allows you to avoid expensive repairs. If your level runs low faster than it should, this could indicate that it is malfunctioning.

To perform a check-up, make sure that the engine is cool. This means that you cannot check the reservoir while the vehicle is running. Allow a few hours after driving before removing the cap. Doing otherwise could cause burns, especially when the coolant is still hot. Next, check for markings found on the side cover of the plastic overflow bottle. It is directly connected to the cooling system.

This bottle has a bright cap, usually orange. It is transparent, allowing you to see the fluid it contains. The level should be in between the markings that show the maximum and minimum fluid level. If the level goes beyond the minimum, consult your user manual. There, you can find the right type and base coolant for your car and refill the fluid right away. You may also consider flushing the system if you see debris floating inside or if the color of the fluid is rusty and brownish.