How does engine hydraulic shock occur? What is water hammer in a car engine and how to avoid it. How to protect communications in an apartment from water hammer

Most motorists are well aware that cars do not particularly like contact with water. Therefore, drivers try in every possible way to avoid driving through deep puddles, even in urban conditions.

SUVs are more passable in this regard; they are capable of passing through fairly difficult off-road areas, fording rivers and sometimes almost up to the windshield.

But regardless of the vehicle you are using, you should never forget about such a phenomenon as engine hydraulic shock. This is an extremely dangerous thing that can happen not only off-road when trying to cross a river or lake. This happens in normal urban conditions, when there is a heavy downpour or a car tries to drive through a deep puddle.

What is this

Let's start with the very concept of engine hydraulic shock and how it occurs. In normal operation of the power plant, the air-fuel mixture enters the working cylinders. The pistons compress it, from compression or a spark plug it ignites, the resulting force pushes the piston back and this is repeated many times. This phenomenon allows the vehicle to move.

But now you need to figure out what this engine hydraulic shock means. It occurs when, in addition to fuel and air, there is additional water in the cylinder. The cycles are not interrupted; compression and ignition occur. The only and most important problem is that water, unlike the air-fuel mixture (actually gas), practically cannot be compressed.

When the amount of water is small, nothing bad usually happens. Moisture evaporates quickly due to high temperature. But when the volume of water increases and the piston is at top dead center, problems begin. The connecting rod is deformed, and other destructive processes occur.

Since water is practically not compressed, during the compression stroke the piston moves upward, but rests against a layer of water. It does not allow you to completely finish the beat and reach the top point of your movement. The cycle does not end; a phenomenon called water hammer occurs.

Water hammer can lead to extremely serious and dangerous damage to engine structural elements. The first to suffer is mainly the connecting rod. This happens due to the fact that the connecting rod is located between the piston, which rests against the water, and the crankshaft, which rotates by inertia. This leads to deformation of the connecting rod. It bends because it is actually sandwiched between two elements. Like a hammer and anvil.

Based on everything said above, water hammer can be called water entering the piston space inside the combustion chamber. Because of this, an active destructive process begins, during which engine elements can bend and deform. Connecting rods and pistons suffer, and cracks form in the cylinders.

It all turns around. And sometimes, if you don’t make the right decision in time and continue driving on a damaged engine, a complete replacement of the power plant is required. And these are extremely impressive financial costs.

Causes

Motorists are sure that the problem of water hammer is relevant only for those who have recently been behind the wheel. Allegedly, only beginners make such mistakes, and this will never happen to experienced drivers.

But this is a big misconception. No one is fully insured against water hammer, which is why those who have spent many years behind the wheel without any serious incidents or mistakes also encounter this phenomenon.

It is extensive experience that often plays a cruel joke on a motorist. He is sure that he knows and can do everything, and therefore he really forgets basic things. Plus, transferring from one car to another, which differed in their characteristics and capabilities, leads to making banal mistakes.

There are 3 main reasons that lead to water hammer in the power plant.

1. Deep puddles. If the driver often likes to drive at high speed through a fairly deep puddle, the likelihood of encountering a water hammer increases significantly. This is because a deep puddle allows water to easily penetrate the air filter. The combustion chamber is already very close to it. After the filter, there are practically no obstacles on the way into it.
2. Water barriers. Not only SUV owners try to overcome various water obstacles. Even when a body of water, river or lake seems small, it’s worth taking risks only if you have full confidence in your car. Otherwise, the water level reaches the air intakes, the liquid follows into the air filter, and from there it is sent to the piston system of the power plant.
3. Engine malfunctions. Even on a completely sunny day, in the absence of puddles and water barriers, there may be water in the cylinders. This can be explained by cracks and deformations of the cylinder head gasket. If this happens, the coolant acts as water, which leaks through the damaged gasket. When water hammer is caused precisely by a violation of the integrity of the engine structure, it often manifests itself when the engine starts.

These factors can be excluded. But not all drivers carefully monitor, and sometimes they simply forget about the need to be careful when trying to overcome some puddles or other water obstacles.

Characteristic signs

Drivers should also know how to identify water hammer. There is no specific sign here. This phenomenon is determined by several characteristic symptoms.

1. Water in the collector. The primary signs of water hammer occurring in the engine appear in the form of water. It is water that gets into the fuel in the combustion chamber of a gasoline or diesel engine and interferes with the normal completion of the cycle. If there is additional water in gasoline and air in sufficiently large quantities, water hammer is inevitable. And first you need to look for traces of moisture on the intake manifold. Moreover, such symptoms are determined in the very first days. Otherwise, all the water will evaporate, and it will be unclear whether it is really the problem. It’s not difficult to figure out how to determine water hammer in the engine system. If there is water, then the diagnosis is correct.
2. Air filter. Another option for finding out if the engine had such a dangerous water hammer. It is not always possible to check the manifold due to the design features of the engine. That's why it's worth looking at the air filter. It is not difficult to study even in the field. If it is deformed (the filter paper elements are wet), wet streaks are visible, then these are characteristic signs of an impact.
3. As a result of the impact, the connecting rod was deformed, which is why the piston is no longer able to reach the top point. With this phenomenon, the carbon streak will increase. This happens in proportion to the deformation of the connecting rod itself.
4. Due to deformation, a bent connecting rod is not able to create uniform movement for the piston. Therefore, the piston adheres stronger to one side and weaker to the other. Hence, uneven carbon deposits are observed.
5. Also, signs that an engine hydraulic shock has occurred appear in the form of deformation of the piston itself. To assess the condition of the engine, it is worth looking at the presence of abrasions in those places where the piston is in contact with the cylinder, or rather its walls. If an impact occurs with further deformation, the contact marks will go obliquely, and not in a straight line, as happens when the elements are working properly.
6. Water does not always penetrate only 1 cylinder. Therefore, sometimes only one connecting rod breaks, and in the remaining cylinders these elements only become deformed and bent. Most often, a fracture occurs in the upper part of the connecting rod. Not all curves are easy to notice. We need to look more closely.
7. Another option is how to understand that a dangerous water hammer has occurred in the engine. But to do this you will have to remove the cylinder head. There is a significant difference in the color of the combustion chambers. One becomes blacker or darker compared to the others.
8. There may be signs of abrasions along the edges of the connecting rod bearings. Explained by uneven load distribution.

To better understand the essence of what is happening, sometimes it is better to send the car for diagnostics to a car service center. It is not recommended to drive on your own. For these purposes, you should contact the evacuation service. Otherwise, you risk permanently damaging the engine.

The symptoms discussed above rarely occur one at a time. Most often this is a combination of several characteristic features. If they are detected, you can accurately and confidently declare that a dangerous water hammer has occurred in your car’s engine.

Actions in case of water hammer

Considering the potential threat of such a phenomenon, motorists are actively interested in what needs to be done and how to act correctly if their engine experiences water hammer.

In this regard, experts and simply experienced drivers give several useful recommendations.

1. Under no circumstances try again. Even if your car interferes with other road users, any attempt to start it can potentially lead to destructive and even more serious processes. Therefore, the golden rule is not to start the engine after an impact.
2. Next, you need to find the air filter on your car and open it. If water is found in the filter during dismantling, your suspicions about possible water hammer have been confirmed. The filter must be dried and the housing thoroughly wiped dry. You should get rid of any remaining water.
3. If we are talking about a car with a gasoline engine, then you need to remove the spark plugs and try to turn the crankshaft by hand. During the cranking process, you get the feeling that the counterweights are catching the pistons or the pistons are starting to jam. If this happens, the car will definitely not be able to drive on its own. When there are no snags and nothing is touched when scrolling, the deformation is insignificant. In theory, it is possible to drive on your own, but in this situation it is better to call a tow truck.
4. After the manipulations have been carried out, when there are no obvious signs of deformation or damage, try cranking the engine with the starter. If you hear knocking or strange sounds, stop trying and stop the engine. You cannot try to start it again. When everything is within normal limits, that is, the water hammer did not cause serious damage, you can start the engine and go to a car service center.

It doesn't matter how serious the blow was. It always requires a mandatory visit to a car service center or self-repair if the driver is well versed in the relevant repair work.

Both strong and weak impacts are often accompanied by certain deformations and minor breakdowns. Even with a minor impact, damage can be cumulative. At first everything will work well and stably, but gradually the situation will begin to deteriorate, the engine will fail, and a large sum of money will be needed to restore it.

It is much better to check everything at once, adjust the engine design, replace damaged elements, and continue operating your vehicle, but without making the same mistakes.

Potential Consequences

The severity of the consequences of engine water hammer directly depends on the actions of the motorist himself. Some make do with the appearance of a bent valve or connecting rod. If the piston is bent, then the restoration task will become more serious, since it is not so easy to return a bent piston to its original working condition.

The fact is that during a water hammer, not only the connecting rods bend, but other elements are also deformed. Whether the impact will result in minor damage, or whether the engine will have to be sent in for major repairs, depends on the driver’s literacy and the correct actions taken by him.

Those who do not turn off the engine after an impact face the most serious consequences. He continues to work, which leads to worsening of the problem and to new deformations. Most often, such an action ends with a major overhaul.

To understand the danger of water hammer, you should consider several of the most common consequences:

• the connecting rod fails;
• cracks form in the sleeve;
• a hole appears in the cylinder block;
• The piston is deformed.

A connecting rod that bends due to strong impacts on both sides usually manifests itself in two ways. If the blow was strong, then the so-called hand of friendship immediately appears. This is the name for the situation when a damaged connecting rod punches a hole in the block and comes out.

The second option is similar to the first, that is, the block is also pierced with a connecting rod. But this happens after several hundred and sometimes thousands of kilometers, since a slightly damaged element accumulates fatigue. Ultimately, the connecting rod still fails. Sometimes even experienced mechanics cannot immediately replace a minor change in geometry. Therefore, motorists who experience water hammer are often advised to immediately replace the probably damaged connecting rod.

But a stalled engine is not always the result of water hammer. Sometimes this happens if water from a puddle or reservoir gets on the motor sensor, or affects the electrical wiring.

Here you can wait a little so that the remaining water drains and everything dries well. If after this the car starts easily without any problems, the problem is not water hammer. Therefore, the movement can continue on its own. But when this happens repeatedly, it is highly recommended to check the condition of the electrical wiring and also change the sensor as necessary.

When water hammer becomes the culprit of the situation, it is strongly not recommended to move on under your own power. Even simple attempts to get the engine running again can result in costly repairs. Stop, call the towing service and ask for your vehicle to be taken to a service center. There, experts will be able to clearly assess what damage the water hammer caused and how much repairs will cost.

How to prevent water hammer

It is absolutely natural and logical to be interested in how you can avoid engine water hammer.

Everyone understands perfectly well how unpleasant this water hammer is and what consequences it can lead to.

The driver has a real opportunity to protect himself as much as possible from such situations. To minimize the likelihood of personally encountering the phenomenon of engine water hammer, you should consider a few fairly simple rules.

1. Maximum ford value. Each machine has its own limitations on how deep it can go in water. On many SUVs this is prescribed as a separate item of technical characteristics. But it also occurs on passenger cars. The key is to avoid submerging the air filter in water.
2. Assessment of the situation. The driver is driving along the road and sees a puddle, ford or other water obstacle ahead. If you have the slightest opportunity to avoid driving through this place, you should take advantage of it. Driving around on the side of the road or finding another road is much better than later eliminating the consequences of a water hammer. If there is no other way, you need to force the crossing with extreme caution. At minimum speed. When the driver sees that the car is sinking more than the permissible level, back up. It is very dangerous to go further.
3. Snorkel. This is one of the most effective elements for preventing water hammer. Snorkels are special pipes that are installed on cars. This is mainly done on SUVs so that the engine sucks in air from the highest possible point. This allows you to safely overcome even the deepest water obstacles. Water will not get into the cylinders due to the installed snorkel.
4. Natural disasters. If your settlement has been hit, rivers have begun to overflow their banks and severe flooding is observed, it is better not to operate the car at all in such conditions. If you find yourself in such a situation, when there is no other way out, try to choose roads that pass through hills. In any lowland, water can accumulate within a few minutes. Where recently a car was calmly driving through a small puddle, soon the cars begin to float. When crossing water, do not gas too much. If water starts to flood the hood, you risk stalling and becoming a hostage to the elements.
5. Checking air ducts. It must be carried out periodically, regardless of road conditions, precipitation and other factors. You never know when you will be faced with the need to overcome a water obstacle. In this case, you need to be sure that there is no damage to the air ducts.
6. Air filter. Drivers are advised to periodically check its condition and replace it in a timely manner. It has happened more than once that punctures and cracks appeared on the filter as a result of long-term use, or due to aggressive driving style. It will be enough to drive in the rain for water to penetrate through these holes into the filter, and the engine will experience water hammer.

Objectively assessing the situation, we can say with confidence that water hammers are extremely dangerous phenomena that can provoke serious and expensive breakdowns.

It doesn't really matter how strong or weak the water hammer itself was. In almost any situation, the power plant will need to be repaired in the future. And it is much better when such repair work falls on the shoulders of competent specialists.

A very serious issue is engine hydraulic shock. Almost any car can get it, and the engine becomes unusable in 70% of cases, however, this is not always the consequences of the water hammer itself, but the incorrect actions of the drivers after it. Today I want to talk in detail about this phenomenon. I will try to answer the questions - what is it and how to avoid it? And also what engine repairs are needed after it. Read on, it will be interesting...

What is engine hydraulic hammer?

It's simple. On a very rainy day, when the puddles are literally knee-deep, the car may experience engine water hammer.

Water hammer – water entering the combustion chambers of the engine (usually through the air duct), followed by the engine pistons hitting this water plug, after which the engine fails. Water can get in in two ways.

The first is when you “fly” into a deep puddle at high speed, water literally under pressure enters the air filter, and then into the combustion chambers.

The second is when the water level is so high that water itself flows into the engine air duct. This happens rarely, but it does happen, for example, that cars from flooded areas of Europe have this type of water hammer.

After water has entered the engine cylinders, the following happens. Water is not a compressible liquid, like fuel or air. After water has entered the engine piston, during the compression stroke (the valves are closed), the piston moving upward hits the water barrier (a kind of impact), the pressure inside the cylinder increases tens or even hundreds of times, but the engine tries to complete the cycle and tries to bring the piston to the top point. Thus, the cylinder where the water got in stops almost instantly, resting - hitting this water plug. This is where water hammer occurs, and therefore critical engine breakdowns occur, usually these are bent “connecting rods”, broken pistons or piston pins, but the most difficult breakdown is a rupture of the engine block, this happens quite often. Now imagine what pressure is in the engine cylinders if the block ruptures.

How to avoid engine water hammer?

And again, everything is simple.

1) There is no need to “fly” through deep puddles at high speeds; there is a very high chance of water getting into the air filter and then into the engine cylinders.

2) Also, you don’t need to overestimate your car when, in a small car, you are practically swimming to overcome a deep puddle, similar to a small lake - a swamp.

In general, as experienced drivers say, if it’s “raining like buckets” and the roads have turned into rivers, then it’s better to wait out such weather at home. And the car will be intact, and you will save yourself from any troubles in the form of holes under water. However, if you still have to drive, then remember one rule: we drive through deep puddles, the slower the better. It is advisable if you drive 5 - 7 km/h, in first gear, no more! So, better drive around deep puddles!

How to behave if you receive a water hammer?

Many people, after crossing a deep puddle at speed, find that the engine has stalled. They try to start the engine (at first it can even turn), but after “bang” there is not even a piece of the block, or you turn the ignition key, but the engine does not turn! These are signs of engine water hammer!

You need to be mentally prepared for it. For example, if you “fly through” a deep puddle at high speed and then the engine stalls, then there is no need to try to start it! If you are trying to start it, and there is water in it, then you just finish it off! There is one simple rule:

« If, after crossing a large and deep puddle, your car stalls, this is the first sign of engine water hammer. Under no circumstances do we “turn” the engine, we calmly get out and unscrew the spark plugs, and that’s it, we don’t know in which cylinder we have water. We disassemble the air filter housing and touch the air filter; if it is wet, it is very bad. After the spark plugs have been unscrewed, now you need to try to “turn” the engine; if there is water in the cylinders, then most of it will come out of the holes where the spark plugs were inserted. The engine is spinning, water is coming out of the holes, consider yourself lucky! However, there is no need to tighten the spark plugs, we call a tow truck and go to a service station, where the engine cylinders and the engine itself must dry completely, you won’t do this yourself, if only because it is necessary to remove water not only from the cylinders, but also from the air filter and the air duct pipe.»

This is a smaller problem after such an event - however, it often happens that the engine does not turn or the cylinder block is torn, then only repair.

Engine repair after water hammer

To say that it is expensive is to say nothing! It is very expensive! Okay, if your “connecting rods” are bent, it’s not so bad, you need to change the entire piston-rod group, which is no small thing! But if your engine block is torn, then you will need not only a new cylinder block, but also a new piston and connecting rod group, plus all this needs to be assembled with high quality and delivered in the end, the price will be very high. Repairs along with replacement of the engine block can cost from 200 to 400 thousand rubles, it all depends on the class of your car. Easier . You will not be able to do the repairs yourself unless you are an experienced engine technician.

To sum up my article - I want to warn you again, don’t drive through deep puddles, drive through them carefully! This is especially true for BOYS

Many inexperienced motorists, while driving through puddles at high speed, often encounter the phenomenon of engine hydraulic shock. What is it and why is it dangerous? More on this later.

What is water hammer

Engine water hammer is the entry of water into the combustion chambers. As a rule, it gets there through the air duct, where, in turn, it flies in in the form of powerful sprays of air. The danger of this phenomenon is that after moisture penetrates into the motor the pistons hit the formed water plug, as a result of which the engine easily fails.

In practice, this looks like a characteristic blow, after which the engine stops and does not start. Moreover, the higher the speed at the moment of impact, the higher the likelihood of significant damage. After all, in this way the kinetic energy of the rotating parts can break almost any metal structure.

How does water hammer occur?

The process of occurrence of this phenomenon can be of two types. Specifically, water can enter the engine in two ways:

1. The car flies into a puddle at high speed, as a result of which water naturally splashes, some of which, under pressure, enters the above-mentioned one, and then further into the combustion chambers.
2. If the car overcomes high water obstacles, the level of which is sufficient to directly flood the air filter with water. Then the situation follows a similar scenario.

More clearly about water hammer

However, as practice shows, most often the cause of water hammer is the first option. That is, as mentioned earlier, drivers who are not aware of the dangers this phenomenon represents rush at high speed through puddles, for which they pay later.

Then everything happens according to the same scenario. Water, as is known, is not compressed under any conditions, unlike air or a fuel mixture. Therefore, during the compression stroke, that is, when the valves are in the closed state, the piston at the end of its movement naturally rests against the water barrier. This process is a real water hammer.

The greater the kinetic energy of the piston (the higher the engine speed), the stronger this blow will be. Accordingly, the likelihood of a critical breakdown increases significantly.

It is worth adding that cars with low suspension (sports) are more susceptible to water hammer. Accordingly, the higher the engine is located, the less likely it is to occur. However, decreasing does not mean that it disappears altogether.

Consequences of water hammer and repairs

The consequences of water hammer can result in the most unpleasant situations, including critical engine breakdowns. In particular, there is a high probability of bent connecting rods or their pins. A very common failure is a ruptured engine block. Therefore, repairing the problem that has arisen is not a cheap matter.

What are the consequences of water hammer for the engine?

Sometimes there is a need not only for a major overhaul of the engine, but also for its replacement. Naturally, the more serious the breakdown, the more expensive the repair. And in this case we are talking not only about purchasing the necessary spare parts, but also about paying for the services of specialists who carry out the relevant work.

How to avoid water hammer

However, it is better to prevent a problem than to correct the consequences of its occurrence. Therefore, every driver should know how to avoid water hammer, and what to do if it does happen to the car.

As noted above, the first and main recommendation is do not drive through puddles at high speed. But if it is raining heavily or you are supposed to drive literally along “rivers,” then it is better to refrain from such trips. It is necessary to soberly assess the capabilities of your car. If you are driving a small car, then it is unlikely that it would be advisable to drive it through a deep puddle.

But if you still need to drive in the described weather conditions, then you need to do it wisely. If you know the road and the approximate location of the holes that turn into deep puddles, that's better. In this case, try to go around them as far as possible. Otherwise, do not speed. It should not be higher than 10 km/h at a significant water level. Engage only first gear. Remember the rule described above - the higher the speed, the worse the potential damage to the engine.

What to do if a water hammer does occur? First of all, don't panic! The first sign that this has happened is the engine turning off after overcoming a significant water obstacle or puddle at high speed. Remember - do not try to start the engine again, so you just finish him off. In this case, you need to get out of the car, open the hood and unscrew all the spark plugs. Then you need to disassemble the air filter housing. If it feels wet to the touch, it means things are bad. In this case, you can try to rotate the motor shaft. If you are lucky, water will flow from the holes where the candles were screwed in. But you still can’t screw them back in and try to start the engine.

What to do if your car stalls in a puddle

Even in this case, not to mention those when such procedures are impossible to perform or they did not end in a positive result, you need to call a tow truck and take the car to a service station. There, using special equipment, specialists will dry the cylinders and the engine itself completely. In addition, it will be necessary to dry the air filter and the air duct pipe.

Remember that the best repair is prevention! Drive carefully through puddles, and you won't be afraid of water hammer.

One of the main problems when operating autonomous heating and water supply systems is pressure drop. Water hammer in the water supply and water heating system resulting from this sudden change can cause serious damage. He needs to be warned, don't you agree?

We will tell you how to prevent the phenomenon and neutralize its negative consequences, ensuring uninterrupted operation of the circuits. Here you will learn what methods are used to eliminate water hammer in systems that transport water to water taps and heating devices.

The article presented for review examines in detail the nature of water hammer. Preventive measures are listed to prevent the occurrence of a dangerous situation. For a visual understanding of this difficult topic, diagrams, photo illustrations and videos are attached.

Water hammer is a short-term but significant surge in pressure in a fluid-filled system. This phenomenon occurs when a fluid flow collides with an obstacle that appears in its path. Typical examples of the occurrence of such obstacles include sudden closure of shut-off valves, sudden stop of the pump, air lock, etc.

Having encountered an obstacle, the flow of water by inertia continues to flow at the speed at which it was moving before the obstacle appeared. The first layers in contact with the obstacle are compacted at the same speed due to the arrival of subsequent layers.

Due to the constant injection of new layers of flow, the pressure rapidly increases, and the liquid “looks” for a way to dump its part in order to discharge it.

Image gallery

A narrow tube, the cross-sectional range of which does not exceed 0.2-0.4 mm, is placed on the side where the liquid enters the thermostat

The shunting method is used when the pipeline is made only of new pipes. This is due to the fact that the presence of rust and sediment in old pipes can reduce the effectiveness of shunting to “no”. For this reason, when using a shunt at the inlet of the heating circuit, it is recommended to install efficient water filters.

Method #4. Using a Super Safety Thermostat

This is a kind of fuse that monitors the pressure in the system and does not allow it to work after the indicator reaches a critical level. The device is equipped with a spring mechanism located between the thermal head and the valve. The spring mechanism is triggered by excess pressure, preventing the valve from closing completely.

Such thermostats are installed strictly in the direction indicated on the housing.

Carrying out preventive work

In addition to strictly following the rules for operating pipelines, timely implementation of preventive measures helps prevent accidents. After all, all processes in the water supply system or heating circuit are interconnected. And the water hammer is only the final destructive “drop” that can lead to negative consequences against the background of the unsatisfactory technical condition of the water supply system.

Pipeline vibrations and pressure changes contribute to the formation of microcracks in the metal structure. Defects formed over time during the onset of water hammer immediately appear in areas of increased internal stress: mechanical joints, bends and welding seams.

Prevention consists of balancing the heating system, which is performed after completion of installation or repair of heating in a private home.

The main set of works performed during prevention:

• security group health check: safety valve, air vent and pressure gauge;
• periodically checking the pressure behind the expansion tank membrane, and if unsatisfactory results are detected, its adjustment;
• testing the system for leaks and checking the degree of pipe wear;
• valve position tracking shut-off and control valves for leaks;
• regularly checking the condition of filters that retain scale, sand and rust particles; if necessary, clean and rinse the elements;

Prevention aimed at maintaining the good condition of the plumbing system includes simple types of work. But you shouldn't ignore them. After all, this can lead to significant waste of money and time for full-fledged repair work. After all, if the situation repeats, the elements of the system will soon fail. And repairs after that will cost much more.

Please ask questions and write comments in the block below. We are waiting for your stories about how you recorded a water hammer in the system or noticed its consequences. I'm interested in your opinion on the information presented.

There are probably a lot of people who like to watch on YouTube how some crazy guys, after a torrential rain that has flooded all the drains on the streets, are briskly driving along flooded highways in their cars. As a result of such “valiant” overcoming of a water obstacle, the car may stop abruptly, and the engine may suddenly stall. With a high degree of probability, we can assume that it was he who visited you - the water hammer of the car engine.

Fans of extreme sports can be “delighted” with one more message: it is enough to rush through a large puddle at good speed to receive such a “gift”. It is for this reason that many drivers reduce the agility of their iron horses on days with high humidity.

After such frightening stories, let's now figure out what mechanisms and conditions lead to water hammer in a car engine.

Engine water hammer - what is it and how does it happen?

So, your car is parked in the middle of a large puddle, and no matter what you do, you can’t start the engine. Don’t rush to immediately think about the bad, don’t panic, open the hood and lift the cover on the air filter (for blondes, this is a big black pan in the middle of the hood on some brands of cars). If there is water there, then accept our “congratulations”: a water hammer has come to you! If the filter has no traces of moisture, then the reason for the stop may be something else.

The video is an example of how a car engine experiences water hammer when driving through a deep puddle:

The whole problem is this: the hole through which the air passes is the only entrance from where water can enter the engine cylinders.

The density of H 2 O significantly exceeds that of the combustible mixture, and therefore the piston is not designed to withstand the resistance of the substance during compression. The crankshaft continues to move the connecting rod, which has no choice but to bend under the force of pressure coming simultaneously from above and below. The piston becomes warped and gets stuck in the cylinder. And that’s it: the “heart” of the car stopped!

But this is still half the problem: if the crankshaft managed to literally attempt to move downwards, pulling the connecting rod along with it, then the entire piston simply breaks “to shreds”, simultaneously causing a severe blow to the shaft itself and piercing the side of the engine.

Needless to say, after such injuries, there is no need to talk about any movement: the engine has come to an end, and it’s time for him to order a funeral. Now you will have to spend a lot of money on installing a new engine, and in the near future you will have to think about evacuating the vehicle to a garage or car service center.

It is especially important to remember: if you are not sure that a water hammer has occurred, it is better not to try to start the engine. The fact is that when a simple jamming occurs, you can still somehow make repairs and get away with less expense. Otherwise, nothing can help the motor.

What to do next

Various tips on what to do on the spot are good for drivers who have extensive experience and have had to deal with water hammer before. We will assume that this phenomenon took you by surprise for the first and last time, and therefore there is no need to pretend to be a supermaster, and it is best to begin identifying the causes of the problem in the garage, in a calm environment.

When the car is delivered to the garage, take measures to dry the engine. To do this, remove the covers of the distributor-distributor and air filter, and remove the spark plugs.

After the machine has sat for at least 3 or 4 hours, use a syringe to inject a small amount of machine oil (approximately 20-30 g) through the sockets in which the spark plugs were installed. Then, if your car allows it, you need to try to turn the crankshaft.

Video - Gelendvagen water hammer:

If you managed to make one revolution, consider yourself very lucky and the connecting rods are intact. Anyone who has studied well in a driving school knows perfectly well the precision with which engine parts are fitted and understands that the slightest misalignment will not allow this cycle to complete.

Everything seems to be in order, but God protects the best, and therefore checking the cylinders will not be superfluous. The most common malfunction is low engine compression. It occurs due to the fact that there is a gap between the piston rings and the cylinder walls, or the valves are deformed. This can also happen with water hammer.

Loss of compression leads to the fact that the car can move jerkily, and engine power drops. The ignition of the flammable mixture, due to its leakage through the gaps, may occur unstably.

To make sure that there is no weakening of the chamber pressure and leakage of the air-gasoline mixture, it is necessary to measure the compression at the moment when the spark ignites. For such a study, there is a compression meter - a device that looks like a pressure gauge, but measures the pressure in the combustion chamber of the cylinders.

How to measure compression

It is difficult to do this operation alone, and therefore it will not be superfluous if you invite one assistant.

You have already completed the first step: the candles are turned out. Now make sure that the parking brake is set and the gear lever is in neutral.

If your vehicle has a choke control, open it fully. In the case where the position of this part is controlled by an automatic machine, you will have to “uncork” it manually, using suitable tools.

Attach the compression gauge to the spark plug socket of the first cylinder. Then ask your assistant, sitting behind the wheel, to turn the engine flywheel with the starter by briefly turning the ignition key. Approximately 5 revolutions should be completed.

The compression gauge must be pressed tightly against the spark plug socket, so you will have to use force. Write down the device data and move on to the next cylinder.

After all measurements have been taken, compare the largest and smallest readings. The discrepancy in pressure parameters should not exceed 15%. When the pressure is less than 8 bar, the engine is faulty and specialist intervention is necessary, as there is damage to the valves and piston rings.

What if the compression is okay?

After checking the pressure in the cylinders and making sure that there are no violations, ask your partner to do the last useful thing: expel the water from the cylinders. To do this, let him turn the ignition key for just 10 seconds so that the starter turns the flywheel with the crankshaft.

Now we bring all the units into working order: put the spark plugs in place, put on the covers, connect the wires. We do a test run of the engine and listen intently to its sounds. If you do not have experience in identifying problems by sound, or have hearing problems, try listening to the beating of a car’s “heart” in the same way as a person’s: through a medical phonendoscope.

The motor should run smoothly, without knocking or unnecessary vibrations. If there is a knocking sound, or the engine is “feverish”, refuse further experiments. Apparently, the connecting rods were bent after all, and now only a specialist can help the problem.

Diesel engine features

For a diesel engine, water hammer is almost always fatal. It will no longer be possible to check the consequences of a gasoline type, since there are no spark plug sockets on the unit. If you suspect such a “disease,” then the best option is to call a tow truck and tow it to a service center.

Of course, if there is no money, or a period of laziness has come, the car can be delivered to a car repair shop later, but then remember that the water inside the cylinders will quietly do its job, allowing corrosion to eat away at the metal. Do you have the money for extra grinding or boring? Then you don't have to rush too much.

I must say that you will already have a lot of financial problems, especially if the walls of the block were pierced by fragments of scattered piston parts. In essence, this is a complete overhaul of the engine. So if you have a diesel engine, you will have to think about bravely overcoming puddles with more responsibility than the owner of a car with a gasoline engine. Although any driver must take action to prevent water hammer in advance.

How to avoid water hammer when driving a car

So, to prevent an unpleasant thing called “engine water hammer” from overtaking you at the most inopportune moment, especially during nasty heavy rain, thunderstorms or hurricanes, try to follow the simplest rules.

Remember that the air intake is the weakest point and avoid “big water” at all costs. Take it and never run into a large puddle while accelerating: water can not only get into the engine, but along the way you can get your wheel into an open well and damage the chassis. In addition to the engine, water can flood the distributor, ignition coil or other devices, and then another unpleasant problem associated with drying contacts will be added.

In general, try to stay close to the edge of the puddle, slowing down so that the “waves” are smaller.