How to Flush a Radiator

Ken

Updated: March 22, 2022

If you’ve ever run out of hot water while showering, you know the importance of a functioning radiator. But what do you do when your radiator starts to leak? Flushing a radiator is a process that can help remove built-up sediment and restore proper function. In this article, we’ll walk you through the steps for flushing your radiator. Let’s get started!

What Is a Radiator Flush?

A radiator flush is a process of removing any sludge or sediment from the radiator. These sediments are found in radiators due to water evaporation, which causes some minerals to precipitate out. By removing these sediments, the cooling performance of the radiator is increased while also preventing build up on engine components and reducing corrosion.

So, radiator flush is a procedure which involves draining both water and antifreeze from a car’s engine cooling system, typically by way of the drain cock located at the bottom of the radiator. This allows for any built-up sludge or sediment to be removed from the system, either by flushing with a hose or power washing. It also helps prevent corrosion, which can lead to clogged tubes and leaking radiators.

What Does Radiator Fluid Do?

Radiator fluid or coolant is a mixture of chemicals that helps to keep the car engine from overheating. It does this by being in the car’s radiator, which sits right behind the front grille on most cars. The radiator works to dissipate heat from the engine and condense it into water droplets and then drain them out of the system completely. If you don’t maintain your vehicle’s cooling system with regular flushes and inspections, corrosive deposits can build up and clog your radiator and heater core (a separate component inside the HVAC). When this happens, it can cause several problems: one, your car won’t get as hot as it should when it’s supposed to; two, fluids like oil may not be able to get through the engine as well, which could cause a number of issues; and three, you may end up having to pay more for repairs.

One of the best choices to use in your car is Prestone Total Cooling Syststem Cleaner for Radiator, Heater Core, and Hoses

Signs You Need a Radiator Flush

Radiator flushing is a process that uses pressurized hot water to clear away minerals and other deposits that build up inside your heating radiator over time. If you’re not sure if your radiator needs it, here are some ways to tell:

The air coming from the vent feels cool rather than hot.
When you touch the radiator, it doesn’t feel hot to the touch.
The radiator emits a strange smell when you turn on the heat.
The paint or wall around the unit is peeling off.

Flushing will eliminate sediment build up that can block heat transfer between the water and copper tubing inside your radiator. This is especially important if your family’s comfort level decreases dramatically when switching from winter heating to summer cooling mode. Drastic temperature changes cause sediment to move around in the piping system and become lodged, which can reduce a radiator’s heat output up to 70%.

Rather than purchasing an entirely new radiator, flushing is a less expensive and more efficient way to solve your problem. Read on the learn how to flush a radiator yourself using ingredients you probably already have at home.

How Often Should You Perform a Radiator Flush?

Are you looking into having a radiator flushed? If so, you’ve come to the right place. Radiator flushes are used when your heating system is not working properly and metallic particles have been released from the cooling process. These particles can cause damage to your home’s plumbing, reduce the efficiency of the heating system, and even make breathing difficult for people with asthma or allergies.

A flush should be performed every two years to prevent buildup over time. This can vary depending on driving conditions and usage of antifreeze. For example, a vehicle that is used in areas with a lot of salt on the roads may need to have their radiator flushed more frequently.

Why Is It Important to Make a Radiator Flush?

Through time, your radiator will gather deposits of minerals and other substances. This can cause it to work much less efficiently than when you first bought it. To prevent this from happening in the future, a radiator flush is an effective way to clean out all dirt and grime that has started to build up inside. It also helps prolong the life of your radiator by removing any existing damage and preventing further corrosion or mineral buildup in the future.

By flushing your radiator properly , you’ll be able to stay comfortable year-round without worrying about how well it works.

How Do You Do a Radiator Flush?

Radiator flushing is the best way to remove harmful deposits from your cooling system that can clog or restrict its flow, which can cause it to overheat during heavy usage thanks to air pockets staying inside of it even after you’ve filled up all of your coolant/antifreeze again in these steps. Flush your radiator using this guide, then be sure to check it out for any signs of trouble like bubbles or loose pressure elsewhere on the car before taking it out onto the road again! You’ll need some water (distilled if possible), some coolant/antifreeze (in summer months; winter ones will require more since ice doesn’t melt of its own accord!), a radiator drain cock, a funnel or similar means to get the water and coolant/antifreeze mixed together inside of your car’s engine, some rubber hose caps of suitable size, a length of rubber tubing with an inner diameter about 2-4 times smaller than the outer one on your radiator’s filler neck(s), and a tyre air compressor or similar means of filling up your car’s tires with air for safe driving conditions afterwards.

If the engine is still warm from driving, you can flush it yourself by following these steps:

Get your car up on some ramps or park it on a level surface that’s not paved.
Place a bucket underneath the drain cock to catch any fluid that may come out while you’re draining the antifreeze from the radiator.
Look under your car and locate the radiator’s drain cock, which should be somewhere near the bottom of your radiator – close to where it connects with your engine block or firewall.
Turn off your car and let it cool down so you don’t burn yourself when you go to drain it later on in these steps…and so you don’t spill any hot fluid on yourself either!
Once everything is cool enough for safe working conditions, open up the radiator’s drain cock by turning it counterclockwise with an adjustable wrench or channel locks.
Let the radiator fluid drain into your bucket until it’s completely empty – which could take up to 15 minutes or so. Once that’s done, close up the drain cock with your wrench by turning it clockwise until you feel some resistance.
Make sure your new antifreeze is mixed – often times it comes premixed in a single container, but if you need to make a mix of water and antifreeze yourself, check out this article . It also helps to read the instructions on whatever brand of antifreeze you buy in order to find out how much coolant/antifreeze you should mix together in relation to how many gallons are in your cooling system when everything is topped off.
Add your mixture of antifreeze/water to the radiator, which should be filled with water only, until it reaches about midway up the radiator neck or ‘cap’ where all of your hoses connect into the radiator itself. Also make sure that you don’t overfill it either – check out this article for more information on how to do that .
Take a small length of hose and attach one end to the top radiator port located somewhere near the middle of your car’s engine block where all 3 hoses connect into their respective ports coming off of your car’s water pump. This top port is usually covered by a rubber cap at the very least…so you’ll need to take it off before adding your hose to it as well.
Attach the other end of your hose to the radiator’s filler neck and put some sort of cap or valve on top of it so that air isn’t allowed into your cooling system when you start up the car again in these final steps. That way, you’re not flushing any air into your cooling system as you re-fill it with fresh coolant/antifreeze.
Start up the car and let it run for a good 5 minutes, though longer is always better when flushing out an engine’s cooling system in these steps.
Close the radiator’s filler neck valve or cap to prevent any of the old coolant from flowing back into the cooling system and turning off your car’s engine.
Remove the hose from the radiator filler neck and attach it to a nearby funnel, allowing any fluid that still needs to drain out of your cooling system to do so while you re-fill or top off its entire capacity with fresh coolant/antifreeze.
Make sure that the radiator filler neck’s valve or cap is closed and allow your car to cool down for about 30 minutes to an hour, allowing all of the air bubbles and pockets around and inside the engine block to dissipate without having any extra or potentially harmful fluid forced into them by way of the engine running for this period of time.
Open up your radiator drain cock and let it finish draining out, then re-fill your cooling system with water only to halfway up the radiator neck or filler cap to give yourself some room to add more liquid once you’ve checked all of the other connections in these last steps. Then close the drain cock again when you’re done and go on about your way!
When everything is filled back to where it should be and you’ve got fresh coolant/antifreeze everywhere – including inside and underneath all 3 of your car’s radiator hoses, make sure that all of your tires are properly inflated for safe driving conditions before out onto the road again after all of these flushing and draining steps.
Drive your car for a good 15 to 20 minutes, allowing the engine and cooling system to fully circulate and even out the temperature throughout thanks to the ongoing motion of driving your car around.
Fill up your coolant/antifreeze all of the way if you haven’t already – usually somewhere around 3/4 full will be enough during winter months (depending on how cold it generally gets where you live) as long as everything has been filled back up after flushing out your radiator’s contents in these last few steps and you’ve let your engine and cooling system settle down from whatever was clogging or restricting its flow before. You may need more than one container though depending on how much coolant/antifreeze you drained out in the beginning when you flushed your radiator itself or if your car’s engine ran for a very long time when flushing it.
Check all of your cooling system and radiator hoses – make sure that they’re not leaking any fluids and that there aren’t any masses of bubbles in them or pockets of air trapped within either after everything has been filled back up to where it should be again in these last few steps. If everything is hunky-dory, then your job here is done and well done and congratulations to you!
Make sure that the rubber caps are still attached to the top radiator ports before starting up your car again just so they don’t go anywhere and get damaged.

Follow these steps to flush your radiator, drive it around for 15 to 20 minutes so as to give the engine and cooling system enough time to equalize out any temperature difference you’ve caused by flushing it out like this, fill up your coolant/antifreeze all of the way, ensure that there are no signs of trouble anywhere on your car’s cooling system, and have a safe drive on the road again!