Foaming antifreeze in the expansion tank: possible causes and solutions

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

Operation of any car requires constant care and attention. If any malfunctions are found, immediate action must be taken. You can often see that antifreeze foams - this is due to the loss of coolant properties. There are other reasons for this phenomenon.

Briefly about the cooling system and antifreeze function

To approach the issue competently, you need to understand what role the coolant plays in the car's cooling system.

So, antifreeze is designed for effective cooling of various internal combustion engine components. Antifreezes contain polyhydric alcohols, various additive packages, water and dye. This set of components allows the liquid not to freeze at low temperatures. The liquid was specially created so that motorists could be calm in the cold in winter. Antifreeze moves through the system by means of a pump.

Due to the circulation, the operating temperature of the engine is maintained even under extreme conditions. Do not underestimate the role of the coolant in the proper operation of the car. Antifreezerequires periodic replacement. This is very important.

Why does foam form in the expansion tank?

If the antifreeze in the engine starts foaming, then experienced motorists understand that instead of a quality product, they bought and poured counterfeit into the tank - more often these are not factory mixtures. The second reason is worn out, worn-out cylinder head gaskets. The elastic bands do not provide sufficient compression and are blown through.

Poor quality antifreeze

It was discussed above that antifreeze has a special composition that provides effective engine cooling. The liquid is designed to protect the components and parts of the internal combustion engine from temperature deformations. Due to its formula, the coolant does not freeze even in severe frost.

If the antifreeze foams in the tank, then first of all you should make sure that the quality of the product is filled. The fluid must circulate through the cooling system and through all important key components constantly and even during engine warm-up.

If you fill in a low-quality product, then the principles of fluid circulation will not change, but the air that is in the expansion tank will react with elements from the coolant composition. As a result, the liquid will begin to bubble. Coke and foam are formed.

It often happens that you can see a brown mass in the tank. This is a signal that the antifreeze is of poor quality, not made according to factory technologies, but diluted in garages by unfortunate businessmen.

In addition, if they want to save money, sometimes drivers mix two types ofincompatible liquids. Antifreeze also foams due to the fact that the liquid filled in is not the one recommended by the car manufacturer.

Wear gaskets

Many do not pay much attention to cylinder head gaskets, thinking that this is an insignificant detail in a car that simply exists. But such an insignificant detail can add problems to the driver. If the gasket fails, the driver grabs his head and rushes to the service station with great speed.

In fact, the gasket plays an important role. Let's see why the antifreeze foams in the expansion tank. What tasks does this rubber band solve? It prevents moisture from entering the head of the block into the block itself. When the gasket fails, fluid and free air pass into the expansion tank.

If you add high temperature to this, then remembering the laws of physics, we can conclude: foam will form. It does not appear immediately and in small quantities. If the problem is not solved immediately, then subsequently the bubbles will grow, and then the coolant will turn into a foamy mass. All this will be accompanied by smoke and temperature changes. Auto will show normal temperatures.

Cylinder block problems

Often antifreeze foams because of the block itself. But it will not be possible to solve the problem here with little bloodshed. The solution is a major overhaul. At the same time, not only the head is repaired, but the entire block. A damaged gasket provokes overheating of some nodes. And foam is an additional risk of cracking.

How to deal with foam?

In fact, there are several ways to fight, since there are only three key problems - low-quality antifreeze, worn gaskets, problems with the engine or cylinder head.

Coolant change

This will help if the antifreeze foams in the expansion tank and the liquid itself does not meet the stated characteristics.

First of all, open the tap of the stove - it is not difficult to find it. He is in the car. This is the same valve that regulates the temperature of the heater. The "hottest" position - the faucet will be fully open.

Then unscrew the cap of the expansion tank or the filler part on the radiator. Next, you need to drain the liquid from the system - on many cars, a special tap is provided for this at the bottom of the radiator. If there is none, then the channel is closed with a plug bolt. You should prepare a container for coolant - do not drain it into the ground. The liquid is drained completely, not forgetting to remove the intake manifold hose - this will help protect against the formation of air locks.

After that, fill in a new coolant. The collector hose is installed back and the clamp is tightened. The liquid is poured into the tank or into the radiator to an average level. If necessary, the level is adjusted. When the temperature rises, the liquid tends to expand. Therefore, the level may increase.

Start the engine and warm it up to operating temperature. Only now you can check the fluid level in the tank. Top up coolant if necessary. This completes the process and the problem should no longermanifest.

Cylinder head gasket replacement

The procedure for replacing the engine gasket is actually not complicated. Leaks form at the point where the block head connects to the cylinder block. Why does antifreeze foam in the tank? The reason is overheating. In such a situation, the structure is violated, as well as the tightness of the gasket. It is impossible to delay the elimination of such a malfunction.

On different cars, the gasket changes almost the same. There are differences in the order of dismantling the fasteners. It is worth knowing the tightening torques of the bolts.

To prevent possible violation of the fastener structure and failure of components and elements, the bolts are thoroughly cleaned. Before turning them off, remove excess dirt. If this is not done, then there may be problems with unscrewing during a breakdown.

Bolts are unscrewed as evenly as possible. It is recommended to loosen them from the center. After completely loosening each bolt, remove the head and change the gasket. There are center bolts on the block to properly install the gasket.

Ejection of coolant from the tank

This is another problem that raises many questions from car owners. What contributes to this? There may be several reasons for this. However, the most key of them is a worn-out cooling system. When the engine is running, pipes and hoses experience strong pressure from hot antifreeze, therefore, during prolonged operation, the tank will push the liquid out, and not distribute it through the system.

But the problem isn't limited to used cars. The cause may be a faulty expansion tank. This is due to the poor quality of spare parts or marriage. If there are burrs on the neck of the reservoir, this indicates that the cap does not close tightly and coolant will splash out through the gap.

Another reason is substandard plastic tank. Poor quality material cannot withstand pressure and tears at the seams. At the same time, coolant is poured onto the engine and the entire engine compartment.

Preventive measures

Now we know the causes of antifreeze foaming. To prevent this from happening, it is recommended to change the coolant in a timely manner - its life is two years. You need to buy only quality products. Saving here is not profitable.

Cylinder head more and more difficult. It is impossible to predict the moment when the gasket will begin to blow through. It is also impossible to calculate the moment when the foam goes into the tank or into the radiator. But if antifreeze foams in the radiator, you should quickly solve the problem.