Reasons for squeezing antifreeze out of the expansion tank and troubleshooting
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Reasons for squeezing antifreeze out of the expansion tank and troubleshooting

The normal functioning of the power unit is directly dependent on the correct operation of the cooling system. If problems arise with the latter, then the temperature regime of the engine is disrupted, which leads to various malfunctions. To avoid damage to the motor and failure of the elements of the cooling system, the liquid level in the expansion tank must be regularly monitored and, when it decreases, find and eliminate the malfunctions that have arisen.

Squeezes antifreeze out of the expansion tank

During the operation of a car with a cooling system, malfunctions sometimes occur that are of a different nature. One of these is squeezing the coolant out of the expansion tank. There can be many reasons for this phenomenon. Therefore, it is worth dwelling on each of them separately, having considered the signs of manifestation and the consequences of untimely repairs.

Burnout cylinder head gasket

The most common problem in which antifreeze expels the expansion tank from the tank is a burnout of the gasket between the motor block and the head. The seal can be damaged for various reasons, for example, when the engine overheats. It is possible to determine that the breakdown is caused by a loss of tightness as follows:

  1. We start the engine and open the tank lid.
  2. If, when idling, air bubbles come out of the main hose, then this clearly indicates a problem with the gasket.
Reasons for squeezing antifreeze out of the expansion tank and troubleshooting
If the cylinder head gasket is damaged, antifreeze will leave the system

The breakdown of the gasket can be different:

  • if the seal is internally damaged, white smoke will be observed from the exhaust pipe;
  • if the outer part of the gasket is damaged, the antifreeze will be squeezed out, which cannot be overlooked by the smudges on the cylinder block.

The second option is a rather rare case. Most often, it is the inner part of the seal that is damaged, while the coolant gets into the cylinder. Breakdown of the gasket can lead to serious consequences, namely to overheating and seizure of the motor, as well as to a hydraulic shock of the cylinder head and the appearance of cracks in the body of the unit.

Video: reasons for squeezing antifreeze into the expansion tank

Airing the system

Often, when replacing the coolant or depressurizing the system, an air lock is formed, which is an air bubble. As a result, the stove may not work, the motor may overheat, and the antifreeze may escape from the expansion tank.

You can make sure that the problem is caused by an airlock by blowing through, that is, letting the engine run at high revs. If bubbles appear in the expansion vessel and the liquid level decreases, then most likely the air lock will break.

Expansion tank malfunctions

There are times when the coolant leaves directly from the expansion tank, while smudges can be observed on its body or under it. If the reservoir is located between the body elements and a crack has formed in its lower part, then the part will have to be dismantled to detect a leak. The reasons for squeezing out the coolant can be as follows:

The design of the tank is made in such a way that a safety valve is built into the plug, by means of which the excess pressure that arises in the system during the heating of the antifreeze is released. If the valve starts to malfunction, then, under the influence of high pressure, the coolant will come out through one of the weak points: the joints of the pipes, the thread of the plug.

If we consider the VAZ cars of the "tenth" series as an example, then due to problems with the valve on these cars, the expansion tank ruptures. In this case, the leak cannot be overlooked, since the antifreeze will leave in large quantities through the hole formed, which will also be accompanied by the formation of an abundant amount of steam from under the hood.

Pipe defects

As rubber ages over time, the pipes of the cooling system sooner or later crack and fail. Antifreeze leakage can be detected on a warm engine, since the pressure in the system rises. To identify a damaged hose, it is enough to conduct a thorough examination of each of them. They also probe the joints of the pipes with the fittings of the radiator, cylinder head, etc.

If no hose leaks were detected, but there is a clear smell of antifreeze in the passenger compartment or engine compartment, then this indicates a coolant leak, liquid entering the exhaust system and its subsequent evaporation.

Coolant leak

Often, a low level of antifreeze in the system leads to the problem of coolant ejection into the expansion tank. The result is a rapid heating of the liquid and the motor, followed by overheating. This leads to the evaporation of antifreeze and an increase in pressure in the system. In such a situation, the coolant is constantly distilled into the expansion tank, regardless of the operating mode of the power unit. If, after cooling the power plant, the level of antifreeze persists, then this indicates problems with circulation. If the level drops below the MIN mark, this will indicate a loss of system tightness. In the event of a leak, the cause must be identified and repaired.

Radiator problems

Antifreeze in the reservoir of the cooling system can also decrease due to damage to the main radiator. The most common malfunctions of this device are:

To detect a radiator leak, you do not need to resort to disassembling anything: the problem should be clearly visible, especially if the tanks are damaged.

Damage to the pump

If a puddle of antifreeze was found under the car at the location of the pump, then the troubleshooting should start with this mechanism. However, it should be borne in mind that the engine compartment and some components on different cars are protected by covers, while the coolant can leak out in one place, and the source of the leak is located in another. Water pump leaks can be caused by the following breakdowns:

To more accurately determine the cause of the leak, just reach the pump pulley with your hand and feel the space under the shaft. If coolant drops are found, this will indicate a malfunction of the oil seal. However, this test method is applicable only to cars on which the pump rotates from the alternator belt. If the shaft is dry and the cylinder block near the pump is wet, the problem is most likely in the seal.

Troubleshooting methods

Depending on the breakdown, the nature of the repair will also differ. If the problem is caused by leaking coolant, then this can be identified, for example, by leaking pipes. Liquid spills will also be clearly visible in the form of colored smudges on the expansion tank near the plug. In the event of minor damage to the radiator, it will not be so easy to find the place of the leak, since the device is blown by the counter flow of air and leaks cannot always be detected.

To simplify the leak detection procedure, it is recommended to fill the system with coolant with a fluorescent additive. The slightest smudges can be easily detected with the help of an ultraviolet lamp.

The resulting malfunctions are eliminated as follows:

  1. If there are problems with the expansion tank plug valve, you can try to clean and rinse it. No results will indicate the need to replace the part.
  2. If cracks appear on the tank, it will have to be replaced. Sometimes the expansion tank is restored by soldering, but this option is unreliable, since the case may burst again with the next pressure surge.
    Reasons for squeezing antifreeze out of the expansion tank and troubleshooting
    A burst expansion tank can be soldered, but it is better to replace it with a new one
  3. When the pipes of the cooling system are leaking, they are unambiguously changed. An exception is a crack near the end. In this case, the hose can be cut slightly if the length allows it.
  4. A worn out water pump seal can only be replaced on the classic Zhiguli. On other machines, the entire pump must be replaced.
    Reasons for squeezing antifreeze out of the expansion tank and troubleshooting
    It is advisable to replace the failed pump with a new one.
  5. If the radiator cells are damaged, the product will have to be dismantled and diagnosed in a specialized service. If possible, the radiator can be restored. Otherwise, it will have to be replaced.
    Reasons for squeezing antifreeze out of the expansion tank and troubleshooting
    If the radiator cells are damaged, the resulting hole can be soldered
  6. If, according to the characteristic features, it was revealed that the cylinder head gasket is punctured, then it is impossible to operate the car with such a malfunction. With sufficient experience, the breakdown can be repaired with your own hands. Otherwise, you should contact the experts.
    Reasons for squeezing antifreeze out of the expansion tank and troubleshooting
    If the cylinder head gasket burns out, it only needs to be changed, which may require grinding the surface of the head and block
  7. To eliminate the airlock, it is enough to lift the front of the car with a jack, add antifreeze and gas several times to remove air from the system.

Video: how to get rid of air in the cooling system

If any malfunction occurs on the road, you can add antifreeze or, in extreme cases, water and get to the nearest car service. An exception is a burnt-out head gasket. In case of such a breakdown, a tow truck must be called in order to transport the car.

Most of the problems due to which the coolant squeezes out of the expansion tank can be eliminated on our own. No special tools or skills are required to replace pipes or a pump. Repairing more serious breakdowns, such as replacing the cylinder head gasket, will require certain skills, but this procedure can also be performed in a garage without specialized equipment.

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