The reasons for the knock of the VAZ hydraulic lifters. Hydraulic lifters knock: reasons and what to do. The easiest way to eliminate the knock of hydraulic lifters. If noise appears after replacing the main battery

Today we will talk about the reasons for the knock of the hydraulic lifter and how to solve this problem.

Gas distribution mechanism power plant of the car is a very important component of it, since it ensures the timely supply of air or a combustible mixture to the cylinders and removes exhaust gases from them.

On modern cars, the mechanism with an upper location is most often used. camshaft, which made it possible to reduce the metal consumption of the structure and, as a result, to increase the reliability.

Since the metal expands when heated, and the valves are constantly in the zone high temperature, to prevent it from being pressed, as a result of which it sits loosely in the seat, a thermal gap is provided between the valve stem and the cam of the camshaft.

In this case, the thermal gap has a certain value in order to ensure the maximum possible opening of the valve, excluding its tightening.

Previously, on engines with an overhead camshaft, the thermal clearance was adjusted by placing shims of a certain thickness between the valve stem and the camshaft cam.

The disadvantage of using these washers was the need to periodically check the gap and adjust it by selecting washers.

Now, to ensure the thermal gap, hydraulic compensators are increasingly being used, in the popular way - hydraulics, the use of which eliminated the need to adjust the gap, and all because the gap is regulated by oil pressure.

Hydraulic lifters are located, like adjusting washers, between the valve stem and the camshaft knuckle.

Outwardly, the wetsuit looks like a small piston, so the head has seats for them.

Design and principle of operation

The very same hydraulic compensator design is simple. It consists of a cylindrical piston, the bottom of which receives the force from the camshaft cam.

Inside this piston, a plunger is installed in its seat, through which force is transmitted through the piston from the cam to the valve stem (see photo above).

In its seat, the plunger moves freely, providing a thermal gap.

The hydric works like this: when the engine is running, the cam runs on the bottom of the hydraulic compensator piston and shifts it down. Moving, the piston by means of the plunger presses on the valve, and it opens.

The clearance is adjusted with oil.

The oil pump supplies oil to the head under pressure. In the hydraulic system, it enters the sub-plunger space, and displaces the plunger inside the seat.

The higher the oil pressure, the more it will press on the plunger and the more it will come out of the seat.

With a decrease in pressure, the plunger again enters the seat. Thus, the thermal clearance between the plug and the valve stem is independently adjusted and depends on the pressure in the lubrication system.

Ball valves are installed in the oil supply channels in the head of the block to prevent oil from leaking out of the hydraulics after the engine stops.

Having such an advantage as the absence of the need for adjustment, the hydraulic compensator also has one significant drawback - high sensitivity to engine oil.

Reasons for knocking hydraulic lifters

The hydraulic compensator is still not an adjusting washer, which can only decrease in thickness due to constant friction, it may well fail.

Problems with the work of the wetsuit appear in the form of a clearly audible knock during the operation of the power plant. Moreover, the knock can be in some modes of the motor, while in others it disappears.

Also, the knock of hydraulic lifters can appear when the engine is cold and disappear after the optimum temperature is reached, or vice versa.

The most common cause of knocking on a wetsuit is motor oil, although there are many other reasons.

If, when starting the power plant, a knock of hydraulic lifters is heard, but at the same time it quickly subsides, this is not the reason for their failure.

Just after another stop power unit some of the valves remain depressed due to the location of the camshaft, the oil supply channels also remain open, and the oil from the hydric flows through them.

At startup, the amount of oil in the channels is quickly replenished.

But if the knocking on a cold engine continues for a long time or until the engine is fully warmed up, this indicates a malfunction in operation.

The hydraulic lifter knocks on a cold one.

A knock on a cold one may indicate:

Mechanical wear of the plunger and its seat. In this case, the oil does not maintain its pressure and constantly flows out of the sub-plunger space;
Plunger jamming in the seat due to contamination;
Jamming in the open position of the ball valve due to its contamination;
Clogged oil supply channel. When warmed up, the blockage is washed out by flowing oil and the hydraulic compensator works normally;
Application of oils with high viscosity on cars. When a cold engine is running, viscous oil simply does not have time to enter the hydraulic compensator;
The exhausted resource of the oil, as well as its significant clogging by friction products;
Significant clogging oil filter, as a result of which its throughput drops, and cold oil is not fully supplied to the cylinder head.

The reasons for the knocking of hydraulics on a cold engine are much similar to the reasons for their knocking on a hot one.

Hydraulic lifter knocking on a hot engine.

The appearance of knocking can be due to mechanical wear, seizure of the plunger or valve.

Regarding oil, it is worth noting that a knock on a hot one can be due to a highly flowing oil, then the oil pump cannot provide the proper pressure.

Another reason for knocking, both cold and hot, may be the wear of the oil pump with a subsequent drop in its performance.

Consequences of the appeared knock

It is interesting that the breakdown of the hydraulic lifters does not lead to any damage to other mechanisms of the power plant.

In knocking hydraulic lifters, only the thermal gap is violated, which only leads to a decrease in the power and throttle response of the power plant and an increase in fuel consumption.

But a knock that appears can signal a malfunction in the lubrication system, so it is important to find out why they knock and fix the problem.

As for the use of SOHC and DOHC gas distribution systems on cars, the only difference is in the number of hydraulic compensators installed.

So, on modern cars, including domestic ones, for example, VAZ 2112 and Lada Priora, the DOHC gas distribution system is already used, with 4 valves per cylinder, and therefore with 4 hydrics, the total number of them is 16.

The reasons for the knock that appeared for all cars, including those mentioned, are the same.

The presence of such a number of hydraulics affects only the more difficult identification of a knocked hydraulic compensator, if only one or several of the total number knocks.

Identification of faulty hydraulic lifters

It is, in principle, easy to identify a knocked hydraulic compensator. It is enough to remove from the car valve cover to get partial access to them, which will be enough for verification.

To check the wetsuit, it is enough to use a not thick wooden block.

Checking is carried out by pressing on the bottom of the wetsuit. When an effort is created, it will begin to sink in its seat. It is important when checking that the camshaft cams do not act on the bottom of the wetsuit.

The jammed hydraulic compensator by the created force simply will not sink in the seat, the human influence will not be enough to overcome the forces of the valve spring.

If there is no oil in it for any of the above reasons, the sinking of the hydraulics in the seat will be carried out with much less effort than normally working.

This method can be used to calculate broken hydraulic lifters.

Elimination of the appeared knock

But when a knock appears, it is not necessary to immediately check for faulty hydraulics. Often the knocking is caused by oil, so you can first change the oil along with the filter.

After draining the oil and filling with a new one, the first start will be accompanied by their knocking, since there is no oil in them and all channels are empty.

After a certain time, the knocking should stop. It is only important to select the oil recommended for use by the car manufacturer. It is also advisable to flush the lubrication system before filling with new oil.

If the oil change has not eliminated the knocking, then it is already checked which hydrics are knocking. After identifying faulty hydraulics, they must be removed from the car, which will require dismantling from the camshaft head.

After removing the hydrics, you can try to rinse them in gasoline or kerosene to remove dirt on the plungers, if any.

After rinsing, they are put in place and it is checked if they continue to knock. It is important to make sure that each removed hydraulic compensator is put strictly in its place, they cannot be confused.

If flushing does not help, severe mechanical wear is possible. Then the hydraulic lifters are replaced, since they are not repaired.

Kit for VAZ 2112.

If the wipers are new and filled with fresh oil, but they continue to knock, the oil supply channels may be clogged. Then you will have to remove the cylinder head and rinse it completely.

When flushing the cylinder head did not help, this indicates significant wear of the oil pump, then it will need to be replaced. But this happens very rarely, usually changing the oil, as well as flushing or replacing the hydraulic lifters, fix the problem.

Other malfunctions and how to fix them.

It is better to always look for the cause of the emerging knock of hydraulic lifters sequentially, performing one operation after another, starting with the simplest and moving on to the more complex.

In most cases, hydraulic lifters (HC) fail when the oil channels of the motor are dirty, the working surfaces of the plunger pair and the reversing valve, which are made with a high degree of precision, are worn out.

Contamination occurs in the following cases:

when the wrong oil is used,

when its substitution occurs out of time,

defective filter designed to pass dirty oil through the bypass valve.

From the camera highest pressure oil starts to leak if the seat clearance in the plunger pair is increased. The hydraulic compensator loses the property of "rigidity", therefore, the efficiency of supplying the cam force to the timing valve, to its rod, sharply decreases. A similar situation occurs when the HP chamber valve is worn out. If the engine lubrication system is faulty, the filling of the hydraulic compensator with oil slows down, the timing does not absorb gaps.

The oil must fill the entire internal volume of the hydraulic compensator. When it is not completely filled, its main purpose (elimination of gaps in the timing elements) is not performed. Ultimately, massive loads appear, making themselves felt with appropriate knocks.

If the hydraulic lifter knocks, what can happen? Because of this, the timing parts wear out faster, the engine runs worse. It also leads to breakdowns of parts when particles of worn-out devices enter the hydraulic compensator together with oil. With all this, the knot can be jammed. In this case (looking at the position in which it happened) the valves will clamp or large gaps in the timing will appear. As a result, the power may decrease, the load on the camshaft increases, etc.

To avoid these problems, you should:

Keep the inside of the motor clean and under control.

Change filters and oil within the time recommended by the car manufacturer with a reduction factor of 0.6-0.9, taking into account the operating conditions of the vehicle.

Before each oil change, flush the engine using slow-acting “run” flushes. If the inner surfaces of the motor are dirty, and this was discovered when the timing case was removed, it is not necessary to use quick-acting flushing agents, since various exfoliated particles can penetrate into the internal cavities of the compensator with oil, which will lead to the destruction of the main valve.

Small gaps between moving parts of the main body make it possible to use quality oils- semi-synthetic and synthetic. (10W 30, 5W 40, SAE 0W 40). Mineral oils they are not suitable for this, because are characterized by an overestimated viscosity.

Substitution and diagnostics.

Failure of the hydraulic compensator, one or more, is accompanied by a knock, which can be confused with a valve. You can find a faulty hydraulic compensator using a phonendoscope.

You can make a version of this device on your own, using a metal rod with a diameter of 5 mm and a length of 700 mm. A clipped top tin beer can is attached to one end of a rod, and a wood handle is attached to the middle. The free end of the device is applied in the area of each HA to the head, and the ear is applied to the bank. If there is a suspicion that the GC is in good order, it is removed with a magnet and inspected. If he is stuck and does not give in, use a hook pull. Some hydraulic lifters are disassembled, allowing you to clarify the degree of wear of parts. Care must be taken when handling parts to avoid damaging the surfaces of adjacent parts.

After the retaining ring has been removed, the hydraulic supports should be disassembled. Tapping the body of the hydraulic pusher against the metal surface, carefully shake out the insides. Wash the dirty expansion joint with acetone or other means.

Disassembly of the hydraulic support is carried out directly after removing the retaining ring. The internal parts of the hydraulic pusher should be shaken out by gently tapping the iron surface with the body. A dirty expansion joint must be washed in a solvent such as acetone.

Potholes and scratches are visible on visual inspection. There may also be the formation of depressions. It is possible to keep under control the state of the dismantled hydraulic compensator as follows: if, after filling with oil, it does not compress under the efforts of the hands, it is serviceable. If it shrinks, it needs to be changed. When compressed with a clamp, the working main body is capable of providing strong resistance, and the length is miniaturized only after 30 seconds.

Installation tricks.

In order for the new hydraulic compensator to work correctly after installation, the following rules should be observed:

When installing a new GC, the oil filled at the factory is not removed. After starting the engine, this compound will mix with the oil from the engine lubrication system without negative consequences.

Empty, airborne GCs cannot be installed; they should be previously filled with oil. Otherwise, strong loads may appear already at the first start of the motor.

Directly after installing the main engine on the engine, it is necessary to turn the crankshaft 5-7 times by the ratchet, and maintain a ten-minute pause before starting the engine to take a suitable working position of the plunger pairs under the pressure of the camshaft cams.

In the process of repairing or replacing the hydraulic compensator, the oil system is flushed, the filter is changed, fresh oil is poured into the engine. Checking the oil flow to the seats through the channels occurs visually when rotating crankshaft.

If there is an engine under repair that has passed 150-200 km, GK valve clearances should be changed. If one or a pair of hydraulic lifters has failed, it is better to change the entire set completely.

Bleeding hydraulic lifters.

If the hydraulic lifter knocks when the engine is warmed up, this means airing and partial leakage of oil. In this case, the engine is allowed to run for 2-3 minutes at constant speeds, later at variable speeds, then at idle. If the noise has not disappeared, the whole cycle is repeated, and if necessary, even a couple of times.

If the hydraulic lifters knock, then it is necessary to understand the causes of the phenomenon. It is also known from the school physics course. That the metal expands when heated and contracts when cooled. During the assembly of the engine gas distribution mechanism, this property is taken into account, and the assembly is performed with the specified clearances. Their value is determined by the manufacturer and is stored in the vehicle passport.

Over time, the clearances need to be adjusted and checked in time. Deviation of clearances from a given norm affects the operation of the power unit:

When the gap is reduced or removed, the tightness is broken, since the valve does not completely close, which reduces the compression in the engine cylinders and leads to a decrease in power.
If the size of the thermal gap is higher than the permissible value, then the parts of the exhaust and intake valves of the engine timing mechanism are rapidly destroyed. The specific knock of the valves when starting the engine and on a hot engine indicates an increased clearance.

The permissible values of technological gaps must correspond to the brand of the car and engine, its device features, and be in the range from 0.15 to 0.4 mm. Adjustment is carried out every 15 thousand km, and consists in disassembling the block head. Clearances are set manually using special feelers. When using special devices - hydraulic compensators, the motor does not need to be disassembled, since the clearances are adjusted automatically.

A plunger is inserted into the cylindrical body of this device, which abuts against an elastic return spring. The piston housing has a built-in bypass ball valve with a pressure spring. The movable plunger is held by a lock washer together with the internals of the expansion joint.

Hydraulic lifters differ among themselves depending on where they are installed in the gas distribution mechanism.

If these devices are mounted in special sockets in the cylinder head, then the body of this pusher is made movable in relation to the seat.
When installing a hydraulic compensator in the rocker arm seats, this body is stationary, in contrast to the plunger.

The hydraulic compensator increases or decreases its size due to the overflow of oil and the simultaneous operation of the valve and springs. It is connected to the camshaft, exhaust and intake valves of the timing mechanism and supports the installed thermal clearances necessary for the high-quality functioning of the motor. In this case, their temperature changes are taken into account.

Hydraulic lifters knock on hot

Let us briefly consider the most popular causes of knocking of hydraulic expansion joints on a warm engine and how to eliminate these malfunctions:

Oil change has not been performed for a long time, or it is not of the appropriate quality. In this case, to prevent similar problems, an oil change is required.
Clogged valves... In such a situation, this problem can only be detected on a warm engine. And in a cold state, knocking is not always detectable. The solution to this issue is flushing the system, and replacing the oil with fresh oil, a thicker oil is recommended.
Dirty oil filter... Because of this, the oil does not flow to the hydraulic compensator under the required pressure. As a result, airlock causing this malfunction. The solution is to replace the filter with a new one.
Incorrect oil level... It can be increased or decreased. As a result, the oil is supersaturated with air, which leads to knocking. To solve this problem, add oil to the normal level.
Incorrect operation of the oil pump... If it does not function at full capacity, then this is the reason for the knock of the hydraulic lifters. In this case, it is necessary to check the operation of the pump and set it up for normal operation.
Extended seat for hydraulic expansion joint... When the engine heats up, the landing site expands even more, which contributes to the occurrence of knocking. To prevent the engine from breaking down, you should urgently contact a car repair shop.
Faulty hydraulics and mechanical parts... In this case, the solution to the issue is rather complicated, so it is advisable to contact a specialized car service.

Hydraulic lifters knock on cold

Consider a list of common causes of knocking of hydraulic expansion joints on a cold engine, and how to solve such problems:

The hydraulic compensator itself is faulty... But a similar knock is also characteristic when the engine is warmed up. The cause of a malfunction of the hydraulic compensator can be damage to the parts of the plunger pair, its jamming due to the penetration of dirt into the mechanism, a malfunction of the valve allowing oil to pass through, wear of the external mating surfaces. To eliminate this malfunction, diagnose in a specialized workshop.
Too thick oil that has expired its service life. The problem is solved by replacing the oil with fresh one.
The valve of the hydraulic compensator is leaking... This causes oil to drain when the engine is not running. Together with this, the process of air saturation of the hydraulic compensator is carried out. But this effect is not found if the air is replaced with oil. To remedy the situation, you can bleed the hydraulic compensator or replace the valve.
The inlet is clogged... This refers to the oil pumping hole. When the engine heats up, the oil flowing through the hole is naturally diluted. In order for the oil to start flowing through the hole again, you need to try to clean it.
The temperature mode does not match the operating parameters... Some oils are not suitable for cold temperatures. Its density does not correspond to the working conditions. In this case, it is necessary to fill in the oil recommended by the plant, which can maintain the parameters even in severe frosts.
Hydraulic compensator valve leaks oil, which flows back through the valve, and the hydraulic compensator is saturated with air. When the engine is turned off, the temperature decreases, the oil also changes its characteristics. Until the motor has warmed up, oil will not flow into the system. To fix the breakdown, you need to replace the hydraulic lifter or valve.
Clogged oil filter... In such cases, the solution is always the same - the usual replacement of the filter with a new one.

Knock in new hydraulic lifters

This is normal at first while the car is new. But if the knocking does not disappear in the near future, then it is necessary to identify the problem. If we consider that such hydraulic expansion joints did not give in to wear, then the reason is most likely different. However, it is recommended that a warranty be issued when purchasing a new kit. So you can warn yourself in the event of a defect or an inappropriate option of hydraulic expansion joints.

The knock of new expansion joints is often associated with incorrect installation, as a result of which oil does not pass. Other various problems are also revealed by such a reason that the expansion joints cannot be pumped, since oil cannot reach them. Clogged oil channels are to blame for this, as well as a broken oil pump and many other malfunctions.

Is it possible to operate the car with a knock in the hydraulic lifters

If you quickly answer the question posed, then you can ride, however, you need to quickly eliminate this malfunction, since there is:

Additional noise in the engine compartment.
High vibration.
Excessive fuel consumption.
Violation of the ecology, as the smokiness is increased exhaust gases
Decreased elasticity of management.
Loss of motor power.

When a faulty motor is running, it can completely fail. Therefore, it is forbidden to operate a vehicle with faults in the timing mechanism. The sooner the repairs start, the cheaper it will cost.

Since there are several such elements in the engine, it is required to determine before replacement which compensator makes a knock during operation. In car services, the identification of a faulty part is carried out special equipment for measuring noise characteristics. Acoustic diagnostics in this case became effective way identifying a faulty hydraulic lifter.

You can also diagnose such a part on removed engine... To check these parts, you will need to remove the valve cover, then you need to push each expansion joint separately. Parts that will easily sink when pressed have low oil pressure, which indicates a breakdown. The hydraulic compensator, which is jammed, cannot be pressed by the effort of a human hand. An important point is that the compensators are not pressed by the camshaft cam during diagnosis.

How to eliminate knocking

The most correct way to eliminate knocking is to do complete renovation but other options should be tested, such as flushing. This process requires good working skills and a lot of energy. But flushing does not give a full guarantee of eliminating the causes of the noise, since sometimes this cause is hidden not in the compensator itself, but in the poor quality of the oil or in other malfunctions.

There are times when there is a knock on a cold engine, but there is no knock on a hot engine. In this case, it's about heated oil. This is widespread among drivers, and many do not pay attention to this malfunction. If the knocking does not go away after the engine warms up, then you should contact a car service to carry out professional repairs there.

If the knock comes from one compensator, then you can try to eliminate the knock by this method:

Turn the crankshaft until the valve opens, which matches the knocking compensator.
Rotate the valve and spring by an angle to move the parts that are not positioned correctly.
Start the engine. If the knocking persists, then a more serious engine check is necessary.

This method is suitable for the Priora, as well as for the VAZ-2112. If the engine knocks, being cold, then there is nothing wrong with that, since the oil is still thick, and the knocking will disappear when the engine warms up. When a cold engine knocks, it is allowed to operate the car. And if the valves knock when the engine is hot, then it is necessary to put the car in for repair. If you do not delay, but immediately contact a specialist for repair, then it will not take much time, and the cost of repairs will not be too high.

Many drivers are wondering why hydraulic lifters knock on the Priora. First, it is determined which pusher is making a knock. This is determined by acoustic diagnostics, or by turning off the cylinders one by one.

Next, check the oil pressure in the engine. At low pressure, the oil pump can be replaced. But often the reason is the engine oil itself, which was chosen incorrectly, or it was not filled in full. It is required to replace the oil with the brand specified by the factory, and change its viscosity by adding additives that can stop knocking. Sometimes it is seen that in candle well there is oil when the engine is running under increased load. The oil is drawn out with a syringe and the candles are cleaned or replaced with new ones. Then, for the formation of normal pressure under the cover of the expansion joints, it is necessary to apply a sealant, which was not enough during assembly at the factory.

The procedure for replacing hydraulic lifters

Replacing this part with a new one is a simple procedure that you can do yourself, the car brand in this case is not so important, since the design of the motor and the principle of operation for all power units is the same. The only difference is that when replacing the expansion joint on some models, the cylinder head cover gasket must also be changed. But, in general, the principle of replacement is the same, so you should consider replacing this part as a whole.

Replacement procedure:

Remove the valve cover.
Remove the sprocket from the camshaft. This is done using wire. You just need to hook the part and lift it up.
Check tensioner and damper. If they are too worn out, then they should be replaced with new ones.
Remove the crankshaft mountings and remove the bed.
Remove the rockers and place them in sequence. You can arrange them by numbers to avoid confusion.
Remove the expansion joints one by one. When dismantling different parts, you will have to apply different forces. This can be attributed to vibration while driving. Hydraulic lifters are also numbered if cleaning and diagnostics are planned.
Flush and clean the oil lines and their installation locations.
Screw the hydraulic expansion joints back into place. Be careful when installing, as the part could be damaged if a lot of force is applied. Therefore, it is advisable to use a wrench with a dynamometer.
After installation, install the removed parts according to the numbers opposite to removal.
V mandatory fasten the valves in place with a wide screwdriver.

The dismantled valves can be restored by flushing them, however, most often, after replacement, no one rinses the old parts.

This procedure is completely similar to replacing valves on a Chevrolet Niva. Other vehicles have minor differences. If you do not have sufficient skills, or are not sure of your actions, then it is recommended to contact specialized workshops.

If you are the owner of a car with n52 hydraulic lifters, then in order to remove extraneous sounds, you just need to replace the oil with a more viscous one, for example, 5W-40 oil. This replacement can fix the problem if the oil was to blame. If you drive the car too slowly, it also ruins the car's engine. It is necessary to follow this commandment: slow acceleration with slow deceleration. This will help maintain the engine and also reduce fuel consumption.

Replacing hydraulic lifters on Priora 16 valves with your own hands:

Consequences of knocking hydraulic lifters

If a specific sound is heard during the operation of the gas distribution mechanism, then you cannot hesitate, but you must go to the engine master. If the malfunction of this system is not detected in a timely manner, then the service life of the drive of the gas distribution mechanism will greatly decrease, there is a significant load on the cylinder head, which will subsequently lead to expensive repairs.

Noise appears after replacing expansion joints

Another reason for the knocking of the compensators is their malfunction, since they must be periodically changed. More often than not, this becomes the main reason. If you are replacing the hydraulic lifter, it is recommended that you replace the entire set. There is no guarantee that all expansion joints are in good working order and do not generate a lot of noise. If the knock does not disappear when replacing, then you need to find the reason in other external factors.

Most often, new expansion joints do not knock. However, if the knocking continues, then defective parts are possible, or the reason was not in them. To make sure that this is completely different, you need to check their fastening. Maybe the parts weren't able to shrink as needed and create a similar sound. To eliminate the knocking, it is necessary to tighten them, while the knocking should stop. If the knocks did not pass, then you need to go to the auto repair shop.

Choosing the right oil

As we have already figured out, hydraulic pushers can make a knock due to poor quality oil. Choosing one that is only suitable for your car is quite difficult. When selecting, it is recommended to read its instructions. It is possible that it has the same consistency, but different lubrication properties. It directly depends on the amount of different additives in the oil. Be sure to check the certification of the oil you purchased for your car's motor brand.

An important point is the selection correct brand oil, otherwise you will have to replace other engine elements, and not just hydraulic lifters. Before carrying out an oil change, it is recommended to consult an engine technician.

Hydraulic lifters manufacturers

There is a constant opinion that original consumables are of much higher quality than from other manufacturers. This is usually the case, but there are some peculiarities. Genuine spare parts are often much more expensive than their counterparts. Another feature is that there are analogues original parts superior quality factory parts.

As a result, due to savings or due to quality, car owners can purchase analogues of hydraulic expansion joints. Therefore, we will consider information about the manufacturers we have.

Firm AJUSA... Their price is low, but their quality is appropriate, they practically have only negative reviews... They are often complained about because of the poor quality of production, which contributes to the rapid appearance of knocking and a short service life.
AE products... These are European products that have won fame for quality parts at an affordable price. However, it is believed that these devices begin to knock after a few thousand km.
CompensatorsSWAG... This German manufacturer produces high-quality parts, but there are some moments of the release of low-quality models, inferior to the original ones in steel quality, as a result of marriage or counterfeit.
Hydraulic compensators of the companyFEBI... It is also a German manufacturer, but with a reduced warranty period. Also good quality have expansion joints made in Germany, and in other countries, for example, in China, defective models are often made, which leads to costly repairs.
DetailsINA... The production facilities of this manufacturer are also located in Germany. They are distinguished by their high quality and a long manufacturer's warranty, like any German device. Their parts have excellent reviews from car owners and are very popular on Russian market and in retail chains of the neighboring countries.

Today we will talk about the reasons for the knock of the hydraulic lifter and how to solve this problem.

The gas distribution mechanism of the power plant of a car is a very important component of it, since it ensures the timely supply of air or a combustible mixture to the cylinders and removes exhaust gases from them.

Camshaft location

On modern cars, a mechanism with an upper camshaft is most often used, which made it possible to reduce the metal consumption of the structure and, as a result, increase reliability.

Since the metal expands when heated, and the valves are constantly in a high temperature zone, to prevent it from being pressed, as a result of which it sits loosely in the seat, a thermal gap is provided between the valve stem and the cam of the camshaft.

In this case, the thermal gap has a certain value in order to ensure the maximum possible opening of the valve, excluding its tightening.

Previously, on engines with an overhead camshaft, the thermal clearance was adjusted by placing shims of a certain thickness between the valve stem and the camshaft cam.

The disadvantage of using these washers was the need to periodically check the gap and adjust it by selecting washers.

Hydraulic lifters are located, like adjusting washers, between the valve stem and the camshaft knuckle.

Outwardly, the wetsuit looks like a small piston, so the head has seats for them.

Design and principle of operation

The very same hydraulic compensator design is simple. It consists of a cylindrical piston, the bottom of which receives the force from the camshaft cam.

Inside this piston, a plunger is installed in its seat, through which force is transmitted through the piston from the cam to the valve stem (see photo above).

In its seat, the plunger moves freely, providing a thermal gap.

The clearance is adjusted with oil.

The oil pump supplies the working fluid to the head under pressure. In the hydraulic system, it enters the sub-plunger space, and displaces the plunger inside the seat.

The higher the oil pressure, the more it will press on the plunger and the more it will come out of the seat.

Ball valves are installed in the oil supply channels in the head of the block to prevent oil from leaking out of the hydraulics after the engine stops.

Having such an advantage as the absence of the need for adjustment, the hydraulic compensator also has one significant drawback - high sensitivity to engine oil.

Reasons for knocking hydraulic lifters

The hydraulic compensator is still not an adjusting washer, which can only decrease in thickness due to constant friction, it may well fail.

Also, the knock of hydraulic lifters can appear when the engine is cold and disappear after the optimum temperature is reached, or vice versa.

Engine oil is the most common cause of knocking on a wetsuit, although there are plenty of other reasons.

If, when starting the power plant, a knock of hydraulic lifters is heard, but at the same time it quickly subsides, this is not the reason for their failure.

Just after the next stop of the power unit, some of the valves remain squeezed out due to the location of the camshaft, the oil supply channels also remain open and working fluid from the wetsuit flows through them.

At startup, the amount of oil in the channels is quickly replenished.

But if the knocking on a cold engine continues for a long time or until the engine is fully warmed up, this indicates a malfunction in operation.

The hydraulic lifter knocks on a cold one.

A knock on a cold one may indicate:

Mechanical wear of the plunger and its seat. In this case, the working fluid does not maintain its pressure and constantly flows out of the sub-plunger space;
Plunger jamming in the seat due to contamination;
Jamming in the open position of the ball valve due to its contamination;
Clogged oil supply channel. When warmed up, the blockage is washed out by flowing oil and the hydraulic compensator works normally;
Application of oils with high viscosity on cars. When a cold engine is running, viscous oil simply does not have time to enter the hydraulic compensator;
The exhausted resource of the oil, as well as its significant clogging by friction products;
Significant clogging of the oil filter, as a result of which its throughput drops, and cold oil is not fully supplied to the cylinder head.

The reasons for the knocking of hydraulics on a cold engine are much similar to the reasons for their knocking on a hot one.

Hydraulic lifter knocking on a hot engine.

The appearance of knocking can be due to mechanical wear, seizure of the plunger or valve.

Regarding oil, it is worth noting that a knock on a hot one can be due to a highly flowing oil, then the oil pump cannot provide the proper pressure.

Another reason for knocking, both cold and hot, may be the wear of the oil pump with a subsequent drop in its performance.

Consequences of the appeared knock

It is interesting that the breakdown of the hydraulic lifters does not lead to any damage to other mechanisms of the power plant.

In knocking hydraulic lifters, only the thermal gap is violated, which only leads to a decrease in the power and throttle response of the power plant and an increase in fuel consumption.

But a knock that appears can signal a malfunction in the lubrication system, so it is important to find out why they knock and fix the problem.

As for the use of SOHC and DOHC gas distribution systems on cars, the only difference is in the number of hydraulic compensators installed.

The reasons for the knock that appeared for all cars, including those mentioned, are the same.

The presence of such a number of hydraulics affects only the more difficult identification of a knocked hydraulic compensator, if only one or several of the total number knocks.

Identification of faulty hydraulic lifters

It is, in principle, easy to identify a knocked hydraulic compensator. It is enough to remove the valve cover from the car in order to gain partial access to them, which will be enough for checking.

To check the wetsuit, it is enough to use a not thick wooden block.

The jammed hydraulic compensator by the created force simply will not sink in the seat, the human influence will not be enough to overcome the forces of the valve spring.

If there is no oil in it for any of the above reasons, the sinking of the hydraulics in the seat will be carried out with much less effort than normally working.

This method can be used to calculate broken hydraulic lifters.

Elimination of the appeared knock

But when a knock appears, it is not necessary to immediately check for faulty hydraulics. Often the knocking is caused by oil, so you can first change the oil along with the filter.

After draining the oil and filling with a new one, the first start will be accompanied by their knocking, since there is no oil in them and all channels are empty.

After removing the hydrics, you can try to rinse them in gasoline or kerosene to remove dirt on the plungers, if any.

If flushing does not help, severe mechanical wear is possible. Then the hydraulic lifters are replaced, since they are not repaired.

If the wipers are new and filled with fresh oil, but they continue to knock, the oil supply channels may be clogged. Then you will have to remove the cylinder head and rinse it completely.

Other malfunctions and how to fix them.

This sequence can significantly save money and time.

Experienced car owners always listen to the work of the car while driving. The appearance of extraneous noise often indicates the occurrence of certain problems with the car, malfunctions in its various units and parts. Today we will talk about the reasons for the noise of hydraulic compensators - devices that regulate automatic thermal clearances in the motor.

1 Why can knocks appear in hydraulic lifters?

If the hydraulic lifters fail completely, then they will not knock. But the appearance of extraneous noise always indicates some problems in the operation of the machine. Hydraulic lifters knock usually due to several common reasons:

poor performance of the oil supply valve;
the use of low-quality oil;
mechanical development on the surface of the plunger pair;
the presence of air in the GC;
dirty oil filter;
contamination of oil channels;
too fast heating of the motor;
contamination of the hydraulic lifter;
the appearance of air bubbles in the oil.

When any of the described problems appear, all hydraulic lifters begin to knock, although a breakdown can only be on a separate part. To determine the cause of the knock of hydraulic lifters, you have to carry out a full diagnosis vehicle.

Car diagnostics usually begins with checking for knocking when the engine is cold and warm. The reasons for knocking on cold and hot can be different. So, if the hydraulic lifters knock on a cold engine, the problem is most likely related to the oil. If the oil has not been changed for a long time, then it needs to be changed. The reason for the knocking can also be the hydraulic compensator valve, if it does not hold well, then when the engine is turned off, the oil can simply leak out.

A hot check may indicate the same problems, such as poor quality oil, clogged oil passages, or severe filter wear. But some malfunctions can only appear with such a check:

breakdown of the oil pump;
breakdown of the hydraulic compensator hydraulics;
increased seat of the hydraulic compensator.

It is not always possible to find the cause of the knocks on your own, therefore, if you cannot quickly identify the malfunction, it is better to contact a professional car service.

2 Can you figure out the knocking valve cover yourself and fix the malfunction?

It is impossible to independently determine the only knocking hydraulic compensator. To do this, it is necessary to carry out special acoustic diagnostics, as well as full testing of all vehicle components for malfunctions. This can only be done in a service station, as specialized equipment will be needed.

The easiest way to remove extraneous knocks in the details of the car by carrying out a full repair after diagnostics. You can of course try to eliminate knocking by flushing the device. But flushing does not give a 100% guarantee of getting rid of noise, moreover, it requires some special skills. If the cause of the noise lies in the malfunction of other components and systems of the car or in poor-quality oil, then flushing will not give any results.

If the hydraulic lifter knocks only when the engine is cold, and noises disappear as the engine warms up, then the problem may lie in insufficiently heated oil. This is a common situation that does not harm the car, so drivers usually just turn a blind eye to it. If, however, with an increase in engine temperature, knocking does not disappear, you need to contact a professional to troubleshoot.

There is also a fairly simple way to eliminate knocking in the hydraulic lifter, which is suitable for Lada Priora and VAZ 2112. It involves eliminating knocking as follows:

Crank the crankshaft until the valve corresponding to the knocking hydraulic lifter opens.
Rotate the valve and spring at an angle so that these parts move and return to their original positions.
Start the engine. If the knocks persist, the problem has not been resolved and you still need diagnostics.

3 DIY hydraulic lifters replacement rules

If it is necessary to replace the hydraulic compensator, all the necessary work can be done independently, and the complexity of such repairs practically does not depend on the vehicle model. The principle of replacement is similar, but on some cars, at the same time as replacing the hydraulic lifter, you also have to change the cover gasket.

We start by removing the valve cover, then remove the sprocket from the camshaft using a wire. Just pick up the piece with a wire and slowly lift it up. Now you need to visually inspect the tensioner and damper, if they are badly worn out, it is better to replace them with new ones too.

Next, remove the fasteners from the crankshaft and remove the bed, dismantle the rockers and fold them so that during the installation of the new device you can save the order of their installation. The easiest way is to lay out the parts by numbers. Now we proceed to dismantle the hydraulic lifters. Sometimes, different forces are required to remove these parts. There is nothing wrong. If you dismantle parts for further cleaning, diagnostics and reinstallation, you also need to lay them out in order.

Now thoroughly clean and flush the oil line, as well as all places and assemblies located near the site of installation of new or old gas turbines. It remains only to install hydraulic lifters. You don't have to put too much effort into it. With a strong impact during the twisting of the HK, it can be significantly damaged.

When the main assemblies are installed, you will only have to mount all previously removed parts in the same order. Remember to carefully secure the valves in place with a wide screwdriver.

You may not need to change the main valve to new ones if your car is equipped with n52 hydraulic expansion joints. In them, extraneous noises very often appear due to insufficiently thick oil, and knocking can be eliminated by simply changing the lubricant. Of course, without diagnostics, it is impossible to say for sure that it is the oil that is the cause of the problems, but sometimes it is worth trying. If, after changing the oil, the noises have not passed, it remains only to go to the diagnosis.

Driving too slowly is sometimes the cause of noise and knocking. Very low speeds have a detrimental effect on the engine and other parts of the vehicle. It is recommended to always drive with gentle acceleration and gentle braking. Following this formula will not only save the engine from excessive wear, but also reduce fuel consumption to a minimum.

4 What can the noise of hydraulic expansion joints cause?

If your hydraulic expansion joints are knocking, a trip to a car service would be the best solution. If you do not carry out a complete diagnosis of the engine and other vehicle systems in a timely manner, significant breakdowns, severe wear of the gas distribution mechanism, increased loads on the cylinder head and other components are possible. All this, in case of untimely repairs, can cause very significant financial costs.

Most often, if you immediately replace the entire set of GCs, the knocks disappear without a trace, but not always. If, after installing new parts, noises and knocks persist, the problem may be hidden in external factors and other components of the vehicle. If new, newly installed hydraulic expansion joints knock, there may be several reasons. Firstly, you just might come across defective parts. Secondly, the reason may lie not in the GCs themselves, but in the valves. To check the valves, you need to make sure that they are properly fastened; in some cases, the parts do not shrink properly and create characteristic sounds. To make the noise from the valves disappear, it is enough to tighten the bolts and fix them more securely in the car. If after that the noise has not disappeared, it remains to go to the technical service.

Often extraneous sounds on GC arise due to low-quality oil. It is very important to use the right oil for your vehicle. To choose the right oil, you should carefully read the vehicle manual and the information on the oil container before purchasing it. Different types oils can have the same viscosity, but have different binding properties. These parameters depend on the amount of additives in the composition. It is very important to check the availability of oil certificates for your car's engine by type.

The use of low-quality oil has an extremely negative effect on the condition of the vehicle components. Saving on lubrication can lead not only to the appearance of extraneous noise on the hydraulic expansion joints, but also to a deterioration in the condition of many other parts of the machine. Try to keep track of your car, choose for it good oil and fuel, consult with professionals on all incomprehensible issues, and then the car will serve you as long as possible, with a minimum number of breakdowns.

Design and principle of operation

Reasons for knocking hydraulic lifters

Consequences of the appeared knock

Identification of faulty hydraulic lifters

Elimination of the appeared knock

Hydraulic lifters knock on hot

Hydraulic lifters knock on cold

Knock in new hydraulic lifters

Is it possible to operate the car with a knock in the hydraulic lifters

How to eliminate knocking

The procedure for replacing hydraulic lifters

Consequences of knocking hydraulic lifters

Noise appears after replacing expansion joints

Choosing the right oil

Hydraulic lifters manufacturers

Camshaft location

Design and principle of operation

Reasons for knocking hydraulic lifters

Consequences of the appeared knock

Identification of faulty hydraulic lifters

Elimination of the appeared knock

1 Why can knocks appear in hydraulic lifters?

2 Can you figure out the knocking valve cover yourself and fix the malfunction?

3 DIY hydraulic lifters replacement rules

4 What can the noise of hydraulic expansion joints cause?

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