How To Flush A Radiator [Easy way]

Easy way to flush a radiator described in detail in this post. Flushing radiator of stove required after about 100 thousand kilometers. If heater began to warm poorly.

You can flush radiator, both when dismantling it from seat, or without dismantling it. For self-washing, citric acid, whey, caustic soda, boric, or phosphoric acid usually used, and special tools used at service stations.

How to understand that radiator of stove clogged

There can be many reasons why a stove heats poorly. One common cause is a clogged radiator, blocked internally by coolant decomposition products. To check if it is clean, you need to measure temperature of the inlet and outlet pipes connected to the stove’s radiator when the engine is warm. If one pipe is hot and other is cold, radiator likely clogged. If both pipes are hot but stove still blows cold air, this also indicates a blockage in heater radiator.

Why stove radiators clog

The reason for a clogged stove radiator often lies in the coolant. First, over time, additives in antifreeze break down and form sediment. Second, as the liquid heats up, scale gradually forms, which can also cause corrosion on the surfaces of various components in the engine’s cooling system.

As a result, all that debris accumulates in the thin tubes of the stove radiator’s honeycomb. If the antifreeze is of good quality, these processes occur very slowly. However, if the coolant is of poor quality, not only can it clog the radiator, but it can also damage the engine within a few years.

How to Flush a Car’s Stove Radiator

The radiator can flushed either by removing it or without dismantling it. In the latter case, cleaning agents usually poured directly into the radiator.

Alternatively, cleaning agents can circulated using an additional pump by connecting it to the nozzles, followed by rinsing with water.

Flushing the Stove Radiator Without Removal

It is easier to flush the stove radiator without removing it. There are three common methods: using two plastic bottles, using a suspended large plastic bottle, or using an external water pump. These methods create pressure inside the radiator, allowing the cleaning fluid to circulate effectively.

Rinsing with Plastic Bottles

This method allows you to flush the radiator either when it’s removed or directly in place under the hood. You will need two 1.5-liter plastic bottles, a radiator cleaning solution, and four clamps.

The method works by pouring half of the cleaning solution into the radiator and one bottle. The liquid alternately driven from one bottle to the other by squeezing the bottles with your hands or feet, flushing out the inner cavity of the radiator. This simple and effective method requires replacing the liquid with clean fluid if it becomes very dirty.

Another approach involves cutting off the bottom of a large plastic bottle (5-6 liters) to create a funnel. Hang the bottle higher to create pressure from the fluid flowing out of it. Connect one hose to the bottle’s neck and the radiator’s inlet pipe, and the other hose to the radiator’s outlet pipe, directing it into a bucket. Use clamps to secure the hoses tightly to the radiator pipes.

The cleaning fluid, flowing under pressure from the height, will clean the radiator’s internal cavity. Continue this process until the fluid runs clear.

Flushing the Radiator with a Car Pump

One of the most effective methods involves using an external liquid pump to ensure a constant circulation of cleaning fluid under pressure.

To set this up, you’ll need a car pump with an electric drive, three hoses matching the radiator and pump leads, a battery charger, an immersion heater (to heat the liquid), a container for the cleaning solution, a filter (like a synthetic sock), a cleaning solution, and a stand to keep the container at the pump’s level.

Connect the hoses to the pump and radiator (inlet and outlet), and to the basin containing the warm cleaning solution. Attach the filter sock to the end of the outlet hose. Power the pump using a battery and make sure to connect the charger, as the battery will be under strain.

This creates a closed-loop system where the cleaning fluid continuously circulates through the radiator. Run the system for an hour in one direction, then switch and run it for an hour in the opposite direction. Replace the cleaning fluid with fresh liquid, and repeat the procedure. Finally, rinse the radiator with boiled or distilled water for about 30 minutes in each direction.

Flushing the Removed Radiator

All of these methods can also applied to a radiator that has been removed. This allows for more thorough cleaning, as well as the opportunity to pour cleaning agents directly into the radiator. Additionally, removing the radiator gives the car owner a chance to clean out debris, inspect for damage, and check for signs of corrosion.

How to rinse radiator of the car stove

On modern cars, stove radiators made of two main materials – copper and aluminum.

For aluminum radiators, acidic agents must used, while for copper radiators, alkaline solutions are more suitable. Alkaline cleaners should never used on aluminum radiators, as they will immediately oxidize the surface, worsening the clogging or even damaging the part!

List of Tools for Washing Aluminum and Copper Radiators

Flushing the Radiator with Citric Acid

Citric acid is effective for cleaning radiators made from any metal, including aluminum and copper. Various recipes and proportions can used, one being 20–40 grams of citric acid dissolved in one liter of water. If the radiator heavily clogged, the amount of acid can increased to 80–100 grams per liter (and adjust the volume of the flushing solution accordingly).

Ideally, the pH of the acid solution should tested with litmus paper, aiming for a pH of 3, which optimal for cleaning the radiator.

The citric acid solution can used in the same way as other methods mentioned above, by pouring it into the radiator. Alternatively, you can pour it into the car’s cooling system instead of antifreeze, run the engine for 30–40 minutes, and then let the car idle or take a short drive, leaving the solution overnight.

Afterward, drain the liquid. If it’s heavily contaminated with sediment, repeat the process one or two more times. Finally, flush the cooling system with distilled water and refill with new antifreeze.

Vinegar Rinse

Vinegar is another cost-effective and efficient solution for cleaning the radiator and the cooling system. To prepare the rinse solution, mix 500 ml of vinegar with 10 liters of distilled or boiled water. The process is similar to using citric acid and is suitable for both copper and aluminum radiators.

Serum Wash

Lactic acid, found in milk whey, is great for removing plaque, rust, and debris from aluminum and copper radiators. Since pure lactic acid is hard to come by, natural milk whey (ensure it’s natural!) is a suitable alternative.

You’ll need about 5–10 liters of whey. Before use, filter it multiple times to remove any fat particles. The whey typically poured into the cooling system, run for about 30 minutes, and then drained. Afterward, rinse the radiator thoroughly with hot distilled water, as whey contains fat.

Flushing the Radiator with Battery Electrolyte

Battery electrolyte is also effective in cleaning deposits and buildup. Almost any type of electrolyte can used, and it works on both copper and aluminum radiators (but for a short time!). When working with electrolytes, be sure to wear protective clothing, gloves, a respirator, and safety goggles.

With the radiator removed, fill it with electrolyte and leave it for a couple of hours to allow a chemical reaction to dissolve the dirt and plaque. Afterward, drain the electrolyte, and for the first rinse, use water with a small amount of baking soda (1 tablespoon per liter). Then flush the radiator with clean water in a continuous cycle.

Caustic Soda Flush

Caustic soda (also known as sodium hydroxide or lye) an alkaline solution that can used to clean copper radiators only (never aluminum radiators), And should only applied when the radiator is removed, as it can damage other aluminum parts of the cooling system.

To clean the radiator, use a 10% solution of caustic soda. Always wear protective gear, as caustic soda can cause chemical burns on contact with skin.

The solution should be heated before use, poured into the radiator, and left for a few hours. Drain it afterward and repeat the process two or three times if necessary until the flushed liquid becomes relatively clean. Finally, flush the radiator with clean boiled or distilled water.

How to rinse with phosphoric acid

Orthophosphoric acid, or rather its 85% solution sold in specialized stores, is also well suited for cleaning aluminum and copper radiators of a heater. It is used on filmed with auto radiators. You need to work with personal protective equipment, gloves, and a respirator.

Acid just needs to be poured into radiator and left there for a couple of hours. Then rinse thoroughly with boiled or distilled water. It does not corrode metal but instead dissolves plaque and rust formed inside.

Water rinse

The simplest, but most ineffective remedy ordinary boiled (this is important !!!) or distilled water. However, if you just want to rinse radiator with water, then you need to do this under pressure. In its pure form, it is usually not used, but only as a wash after some of the means.

A special tool for washing the radiator of the stove

For those who do not trust the popular “grandfather’s methods,” car chemical manufacturers have made ready-made products that specifically designed to clean the car’s cooling system.

LAVR Radiator Flush Classic. It can used to flush a radiator made of both aluminum and copper. It sold in banks of 430 ml and 980 ml. A small can designed for the volume of the cooling system 8 … 10 liters. Therefore, its quantity must calculated in accordance with the volume of the radiator. Instructions are on the packaging.

It noted that tool perfectly removes rust, limescale, dirt, and other debris. The price of one small can as of the summer of 2020 is about $6 dollars.

LIQUI MOLY Kuhler-Reiniger. The product also intended for cleaning cooling system. It can be used to clean radiators from any metal.

It removes rust, plaque, debris well. sold in a metal can with a volume of 300 ml, which designed for a cooling system of 10 liters. It costs about $8 dollars.

Hi-Gear Radiator Flush. A distinctive feature of flushing – performs cleaning within seven minutes. It can used to clean any radiators made of aluminum or copper. One 325 ml can designed for 17 liters. Price is about $4.

Please note that after flushing, old radiators may leak, as the accumulated debris inside could simply seal case. Therefore, after flushing with special tools, it is necessary to rinse radiator with water from inside and carefully examine it for leaks in joints.

Frequently Asked Questions