How can you remove an air lock from the cooling system?

The presence of air in the cooling system is fraught with problems for both the engine and other components of the car. In particular, overheating may occur or the stove will heat poorly. Therefore, it is useful for any motorist to know how to remove an air lock from the cooling system. This procedure is quite trivial, so even a beginner and inexperienced car enthusiast can do it. Due to its importance, we will talk about three methods of removing air. But first, let's talk about how to understand that air jams are occurring and the reasons for their occurrence.

Symptoms of airiness

How can you tell if there is an air lock in the cooling system? When this phenomenon occurs, several typical symptoms occur. Among them:

• Problems with the thermostat . More specifically, if after starting the engine the cooling fan turns on very quickly, then there is a high probability that the thermostat has failed. Another reason for this may be that air has accumulated in the pump nozzle. If the thermostat valve is closed, the antifreeze circulates in a small circle. Another situation is possible when the coolant temperature needle is at “zero” when the engine has already warmed up enough. Here again, two options are possible - a malfunction of the thermostat, or the presence of an air lock in it.
• Antifreeze leak . It can be checked visually by traces of antifreeze on individual elements of the engine or chassis of the car.
• The pump starts to make noise . When it partially fails, extraneous noise appears.
• Problems with the stove . There are many reasons for this malfunction, but one of them is the formation of an air lock in the cooling system.

If you find at least one of the symptoms described above, then you need to diagnose the cooling system. However, before doing this, it will be useful to understand what caused the possible problems.

Causes of air locks

Air in the cooling system can be caused by a number of malfunctions. Among them:

• Depressurization of the system .
  It can occur in a variety of places - on hoses, fittings, pipes, pipes, and so on. Depressurization can be caused by mechanical damage to its individual parts, their natural wear, or a decrease in pressure in the system. If, after you have removed the air lock, air appears in the system again, it means that it is depressurized. Therefore, it is necessary to do diagnostics and visual inspection in order to identify the damaged area. You need to pour antifreeze in a thin stream.
• Incorrect procedure for adding antifreeze . If it was filled with a wide stream, then there is a high probability of a phenomenon occurring when air cannot escape from the tank, since it often has a narrow neck. Therefore, to prevent this from happening, it is necessary to fill in the coolant slowly, allowing air to leave the system.
• Air valve malfunction . Its task is to remove excess air from the cooling system and prevent it from entering from the outside. If the air valve malfunctions, air leaks in and spreads through the engine cooling jacket. The situation can be corrected by repairing or replacing the cover with the mentioned valve (most often).
• Pump malfunction . Here the situation is similar to the previous one. If the fiber or seal of the pump allows air from the outside to pass through, it naturally enters the system. Accordingly, if the described symptoms appear, it is recommended to check this node.
• Coolant leak . In essence, this is the same depressurization, since instead of antifreeze, air enters the system, forming a plug in it. Leaks can occur in a variety of places - on gaskets, pipes, radiators, and so on. Checking this malfunction is not so difficult. Typically, antifreeze drips are visible on engine elements, chassis or other parts of the car. If they are detected, it is necessary to inspect the cooling system.
• Failure of the cylinder head gasket . In this case, antifreeze can enter the engine cylinders. One of the clearest symptoms of this problem is the appearance of white smoke from the exhaust pipe. In this case, significant bubbling is often observed in the expansion tank of the cooling system, due to the ingress of exhaust gases into it. You can read more information about the signs of a cylinder head gasket failure, as well as tips for replacing it, in another article.

Radiator cap

Each of the reasons described above can damage the components and mechanisms of the car. First of all the engine suffers because its normal cooling is disrupted. It overheats, causing wear to become critical. And this can lead to deformation of its individual parts, failure of sealing elements, and in especially dangerous cases, even to jamming.

Airing also leads to poor stove performance. The reasons for this are similar. Antifreeze does not circulate well and does not tolerate sufficient heat.

Next, let's move directly to the methods by which you can remove the air lock from the cooling system. They differ in the method of execution, as well as complexity.

Methods for removing air lock from the cooling system

How to remove an air lock from the cooling system of a VAZ classic

There are three main methods by which you can eliminate an air lock. Let's list them in order. The first method is great for VAZ cars . Its algorithm will be as follows:

1. Remove from the engine all protective and other elements that may prevent you from reaching the expansion tank with coolant.
2. Disconnect one of the pipes that are responsible for heating the throttle assembly (it doesn’t matter whether it’s direct or reverse).
3. Remove the expansion tank cap and cover the neck with a loose cloth.
4. Blow inside the tank. This will create a slight excess pressure, which will be enough for excess air to escape through the pipe.
5. As soon as antifreeze comes out of the hole for the pipe, immediately put the pipe on it and preferably secure it with a clamp. Otherwise, air will get back into it.
6. Close the expansion tank cap and reassemble all previously removed engine protection elements.

The second method is carried out in accordance with the following algorithm:

1. Start the engine and let it run for 10...15 minutes, then turn it off.
2. Remove the necessary elements in order to get to the expansion tank with coolant.
3. Without removing the lid from it, disconnect one of the pipes on the tank. If the system has been aired, then air will begin to escape from it.
4. As soon as the antifreeze flows out, immediately replace the pipe and secure it.

When doing this, be careful, since the temperature of the antifreeze can be high and reach +80...90°C.

The third method of how to remove an air lock from the system must be done as follows:

1. It is necessary to place the car on a hill so that its front part is higher. It is important that the radiator cap is higher than the rest of the cooling system. At the same time, put the car on the handbrake, or better yet, put chocks under the wheels .
2. Let the engine run for 10...15 minutes.
3. Unscrew the caps from the expansion tank and radiator.
4. Periodically press the accelerator pedal and add coolant to the radiator. This will cause air to escape from the system. You will notice it by the bubbles. Continue the procedure until all the air is released. In this case, you can turn on the stove to maximum mode. As soon as the thermostat opens the valve completely and very hot air enters the cabin, it means that the air has been removed from the system. At the same time, you need to check for bubbles coming out of the coolant.

As for the last method, on machines with an automatically turned on cooling system fan, you don’t even have to over-gas, but calmly let the engine warm up and wait until the fan turns on. At the same time, the movement of the coolant will increase, and under the influence of circulation, air will leave the system. In this case, it is important to add coolant to the system in order to prevent airing again.

As you can see, the methods of how to get rid of an air lock in the engine cooling system are quite simple. They are all based on the fact that air is lighter than liquid. Therefore, it is necessary to create conditions under which the air lock will be forced out of the system under pressure. However, it is best not to bring the system to that state and take preventive measures in a timely manner. We will talk about them further.

How to bleed air using the VAZ model range as an example

VAZ models have a design advantage in the arrangement of cooling system components - a convenient position of the cooled throttle assembly (carburetor), which is the highest place in the cooling system. The procedure for a Lada Kalina car is as follows (the only tool you need is a Phillips screwdriver).

Fully open the heater switch (to the highest temperature);

Remove the valve cover protective screen;

Video: How to remove air from the expansion tank

The second method of releasing air differs from the first only in that you do not need to force air masses into the neck of the expansion tank with your mouth. All operations are performed with the engine normally warmed up and turned off. This method does not involve any manipulations with the expansion tank cap. Immediately remove one of the two heating hoses from the throttle fittings. If coolant leaks, the hose is inserted into place and tightened. It may not work out the first time, then the operation must be done again. This method requires care and caution, since the antifreeze is heated to a temperature of 90 degrees and is under increased pressure.

The third method does not require any disassembly of the cooling system. True, its effectiveness is not very high. The car drives its front wheels onto an embankment so that the radiator cap becomes the highest point in the cooling system. The radiator and expansion tank caps are removed. The engine starts, the antifreeze temperature is brought to operating parameters. When reducing the volume of coolant, it must be constantly added to the amount recommended by the manufacturer. It is necessary to expel the air lock until bubbles stop coming out of the neck of the radiator or expansion tank.

General recommendations for prevention

The first thing you need to pay attention to is the level of antifreeze in the cooling system . Always monitor it and top up if necessary. Moreover, if you have to add coolant very often, then this is the first call indicating that something is wrong with the system, and additional diagnostics are necessary to identify the cause of the malfunction. Also check for stains from antifreeze leaks. It is better to do this in the inspection hole.

Remember to periodically clean the cooling system. You can read how and by what means to do this in the relevant articles on our website.

Try to use the antifreeze recommended by your car manufacturer. Make purchases in trusted, licensed stores, minimizing the likelihood of purchasing a counterfeit. The fact is that low-quality coolant can gradually evaporate during repeated heating, and instead of it, an air plug forms in the system. Therefore, do not neglect the manufacturer's requirements.

Instead of a conclusion

Finally, I would like to note that if the described signs of airing in the system appear, it is necessary to carry out diagnostics and check it as quickly as possible. After all, an air lock significantly reduces the efficiency of the cooling system. Because of this, the engine operates under conditions of increased wear, which can lead to premature failure. Therefore, if you detect airing, try to get rid of the plug as quickly as possible. Fortunately, even a novice car enthusiast can do this, since the procedure is simple and does not require the use of additional tools or devices.

How to check the cooling system pump?

By checking the pump without removing it from the engine, we can only indirectly assess its performance. When the volume of pumped coolant decreases, the stove begins to heat poorly. But before removing the water pump to inspect the impeller, we recommend checking the thermostat and also making sure that there is no air lock in the cooling system.

After removal, pay attention not only to the integrity of the blades and where the impeller fits on the drive shaft, but also to the shape of the blades. For example, on the VAZ 2121 over many years of production, impellers were installed that differed in the diameter of the pump wheel, the number and profile of the blades. Installing a less efficient pump on a more heat-loaded engine modification will result in the cooling system fan turning on more frequently and an increased risk of overheating.

Be sure to inspect the engine block where the housing fits and the pump itself. Fogging or a slight leak of coolant from the drain hole does not mean that the pump should be replaced. If a significant leak is detected, try to pinpoint the location of the leak. If the leak is only at the junction of the housing and the engine block, most likely the problem can be eliminated without replacing the pump. It will be enough to apply sealant and install a new gasket.

Risk of timing belt breakage

The danger with a misaligned water pump timing belt is that there are no obvious signs of failure. First of all, you need to pay attention to the timing belt. If it is pulled to any side, uneven production is observed, it is necessary to check the pump and rollers. The cause of the misalignment may be a manufacturing defect, bearing wear, or uneven fit of the housing to the engine block (dirty, rusty mating planes). Sometimes the malfunction begins to manifest itself after an accident, when elements of the body or attachments hit the pump pulley.

If a misalignment is detected, the defective pump must be replaced as quickly as possible. Also, do not hesitate to eliminate noise and whistling from the water pump. If wear is critical, the bearing may collapse, thereby blocking the toothed pulley. A jammed pump is guaranteed to lead to a broken timing belt. If on your car the pistons meet the valves when they break, then eliminating the consequences of the malfunction will cost a fairly large sum.

Bearing check

The easiest way to check is a pump whose pulley is in an accessible place and is rotated by a drive belt. It is enough to grab the pulley with your hand and shake it in different directions (video check). If there is a malfunction, you will feel a lot of play. To determine that the noise or whistle when the engine is running comes specifically from the cooling system pump, remove the drive belt and unscrew the pulley by hand. A worn bearing with washed out lubricant will rotate with noticeable noise and rolling motions.