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.
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.
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.
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.
It's just that 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 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 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.
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 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.
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 will simply 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.
The operation of an internal combustion engine is inevitably associated with the release of heat. As you know from a physics course, when heat interacts with a metal, it expands. Motor designers take this fact into account in their design and provide thermal clearances. When calculating thermal clearances, special attention is paid to the valve mechanism of the car, where an error can lead to burnout of the valve or the appearance of knocking in the engine.
To allow auto shops and drivers to control the clearance, the engine valve train has the ability to adjust it. It is required to perform it during the operation of the machine, since worn parts lead to a change in the gap.
Initially, the clearance was adjusted using washers and levers, which was extremely inconvenient, and for the end motorist it was also too difficult. Over time, the designers have proposed a more modern solution - the use of hydraulic lifters. These mechanisms independently choose the required clearance and do not need additional settings. But problems can arise with them, and the most famous of them is the appearance of a knock during engine operation.
What are hydraulic lifters
An automotive hydraulic lifter is a piston with a bottom of the camshaft cam. The piston contains a ball valve, the task of which is to open the flap for the oil to enter the piston cavity. The plunger is responsible for transferring force from the camshaft cam to the valve stem.
During operation, oil enters the piston. It fills the free space, after which it begins to press on the plunger. This leads to its movement together with the piston upwards until the mechanism rests against the camshaft cam. Thus, it is possible to achieve automatic selection of the optimal clearance due to the hydraulic compensator mechanism. When the camshaft cam presses on the hydraulic lifter piston, some of the oil is poured out of it, after which the ball valve blocks the oil path, the piston goes down and a gap is created.
The hydraulic compensator, unlike washers and levers, does not require additional adjustment when engine parts are worn out. The gap is in any case regulated, due to the flow of more oil into the hydraulic lifter.
Why is the hydraulic lifter knocking?
The malfunction of the hydraulic lifter is easy to identify. If there are problems with this element, it starts knocking during operation. The consequence of the knock of the hydraulic lifter is an incorrect or untimely adjustment of the valve clearance, which can lead to problems with the engine.
It is possible to classify the reasons due to which the engine hydraulic compensator knocks according to the conditions of their occurrence. Depending on whether the hydraulic lifters are knocking on a cold or warm engine, there are malfunctions that can cause the problem.
Hydraulic lifters knock on a cold engine
Problems with the operation of hydraulic lifters can arise in two cases: when the mechanism itself is malfunctioning or because of problems in the oil supply system. On a cold engine, the following main reasons can be distinguished why hydraulic lifters knock:
Important: It is necessary to distinguish between the knock of hydraulic lifters on a cold engine and when starting the engine. Many drivers are mistaken in believing that if a characteristic sound is heard when starting the engine, there are problems with the hydraulic lifters. Knocking can occur and subside quickly as some of the valves continue to open (given the location of the camshaft) after stopping the engine.
Hydraulic lifters knock on a hot engine
The causes of knocking hydraulic lifters on a hot engine partially repeat the malfunctions due to which this problem occurs on a cold engine. Here are the problems that are typical only for a warmed-up engine:
The situation when hydraulic lifters knock only on a hot engine is rare. Most often, the problem occurs, both on a cold and on a warm engine, and it is associated with poor oil, a dirty oil filter or damage to the hydraulic compensator.
How to identify a knocking hydraulic lifter
Since there are several hydraulic lifters installed in the engine, it is necessary to determine which one of them knocks during operation before replacing or detailed diagnostics. In service centers, the search for a faulty mechanism is carried out using a special device for measuring the noise level. Acoustic diagnostics is an effective method when searching for a problematic hydraulic compensator.
You can also diagnose the hydraulic lifter on a disassembled engine. To check them, you will need to remove the valve cover, and then make efforts to push each element separately. Hydraulic lifters, which, when exposed to external influences, will be easily recessed, have insufficient oil pressure, which indicates their malfunction. A jammed hydraulic compensator cannot be drowned by human forces.
Important: Pay attention that during the diagnosis the hydraulic lifters are not pressed by the camshaft cam.
What does the malfunction of hydraulic lifters lead to?
Problems with hydraulic lifters do not have a strong effect on the wear of other engine components, but the problem should not be postponed. It is necessary to search for the malfunction of the hydraulic compensator, since problems that arise may indicate a malfunction of the lubrication system.
By themselves, faulty hydraulic lifters will lead to a decrease in engine power, a deterioration in the dynamics of vehicle acceleration and an increase in gas mileage.
What to do if hydraulic lifters knock
In most cases, the clatter of hydraulic lifters is associated with problems in the lubrication system, which are caused by poor oil. Therefore, when extraneous sounds from hydraulic lifters appear on a cold or hot engine, the first thing to do is to change the oil and oil filter.
Please note: The first start of the engine after changing the oil will again be accompanied by knocking of hydraulic lifters. This is due to the fact that after draining the old oil, the hydraulic lifters become "empty".
If changing the oil did not help fix the problem, it is necessary to determine which hydraulic lifter knocks during operation. Having identified a faulty element, you can remove it from the engine and try to rinse it in gasoline or kerosene, and then put it back in place. This will help if the cause of the knocking lies in the contamination of the hydraulic lifter.
Important: It is necessary to install hydraulic lifters after flushing in the position where they stood before removal.
When flushing the hydraulic lifters does not help to solve the problem with the occurrence of knocking in them, the elements will need to be replaced.
The most common malfunction of modern engines is the knock of hydraulic lifters. There are many reasons, most of them related to the quality of the oil. This material will tell you what to do with this malfunction and how to deal with it.
What is a hydraulic lifter and how does a hydraulic lifter work
The hydraulic compensator is a simple device for automatically adjusting valve clearance, eliminating the need to disassemble the engine for maintenance. The hydraulic compensator, in common parlance "hydric", is a miniature hydraulic cylinder that changes its length when the engine oil is pumped inside.
The oil volume compensates for the clearance between the valve stem and the camshaft cam. Oil enters the hydraulic compensator cavity through a valve with a very small hole, and comes out through the natural clearances of the valve pair. How well the “hydric” works depends on the oil flow and on the condition of the plunger pair, the absence of wear or seizure.
How to understand what exactly the hydraulic compensator is knocking
A faulty hydraulic compensator emits a sharp knock, chirp, with a frequency of half the engine speed.
A hydraulic compensator is considered to be faulty if it knocks for more than a couple of minutes after starting the engine or knocks after the engine has completely warmed up. The knocking is heard from above the engine and may be inaudible from the vehicle interior.
Why is the hydraulic lifter knocking?
Reasons for knocking the hydraulic compensator "cold" (with a cold engine):
- Too thick oil, on an unheated engine, does not fit well into the cavity of the hydraulic lifter. It takes time for the cavity to fill with oil.
- Clogged oil line or hydraulic compensator valve... Contamination appears when the quality is low or when the engine oil change period is prolonged, and it can also be products of wear of some engine parts.
- Worn or seized hydraulic lifter plunger. It happens from normal wear and tear or from the ingress of abrasive contaminants into the engine oil.
Reasons for knocking the hydraulic compensator "hot" (on a warm engine):
- Jamming of the hydraulic compensator plunger pair due to normal wear and tear or dirt. Seizures on the plunger block its movement and the hydraulic compensator completely loses its performance. The gap is not selected and the hydraulic compensator knocks.
- The viscosity of the heated oil is too low, oil flows out through the clearances of the plunger pair faster than it is supplied by the pump. Poor-quality oil or oil that is too liquid for a given engine is highly thinned during warming up and easily flows out through the technological gaps.
3. Increased oil level in the engine, foaming of the oil due to mixing by the crankshaft or due to water entering the engine. Check the engine oil level and use only high quality engine oils.
The easiest way to eliminate the clatter of hydraulic lifters
The simplest and most effective way, which helps in most cases, is to add a special Liqui Moly additive to the oil. The additive flushes oil channels, removes impurities and restores oil supply to hydraulic lifters. In addition, the additive thickens the oil slightly, thereby compensating for their natural wear. The additive is added to the heated engine oil; the full effect occurs after about 500 km of run.
How else can you eliminate the knock of hydraulic lifters
- Replacing hydraulic lifters Advantages: guaranteed result. Disadvantages: expensive and long). It should be borne in mind that for some foreign cars, you first need to order parts, wait until they arrive, and sign up for repairs at the service. On most engines, replacing hydraulic lifters will require additional costs for disposable parts such as gaskets or sealant.
- Thorough flushing of the oil system with special flushes, for example: Liqui Moly. Pluses: relatively inexpensive. Disadvantages: The result is not guaranteed.
3. Perhaps, in advanced cases, you will need replacing the oil pump or cleaning the oil lines the engine with its partial or complete disassembly.
What will happen if you do not eliminate the knock of hydraulic lifters
If you do not deal with the elimination of the knock of hydraulic lifters, then you can drive for quite a long time without any problems, but, over time, the engine will run louder, with vibrations, power will decrease and fuel consumption will increase, and then there will be wear of the entire valve train, in particular the engine camshaft. Replacing it is a very expensive undertaking.
Outcome
If the knock of the hydraulic lifters repeatedly occurs, then there is no point in waiting for the worsening of the situation. The addition of the additive will solve the problem and prevent the development of wear for a long time.
VIDEO
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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.
Now, to ensure the thermal gap, hydraulic compensators are increasingly being used, in the popular way - hydrics, 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 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.
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.
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.
It's just that 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 the working fluid from the hydraulic system 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 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.
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 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.
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 will simply 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.
(another name is a hydraulic pusher) performs the functions of automatically adjusting the thermal clearances of the valves of the car engine. However, as many car enthusiasts know, for some reason, it starts tapping. Moreover, in different conditions - both cold and hot. This article describes why hydraulic lifters and knock.
How it works and why the hydraulic lifter knocks
Why do hydraulic lifters knock
Hydraulic lifters can knock for a variety of reasons. This is usually due to problems with the oil or oil system, engine hydraulics, and so on. Moreover, the reasons differ significantly depending on the state of the engine - hot or cold.
Hydraulic lifters knock on hot
Let's list briefly the most common causes of knocking hydraulic lifters on a hot engine and what to do about it:
- Oil change has not been carried out for a long time or it is of poor quality.
What to do- to avoid such problems, it is necessary. - Clogged valves... At the same time, the uniqueness of the situation lies in the fact that this problem can only be detected when the engine is hot. That is, with a cold engine, there may or may not be a knock.
What to do - flush the system, and also replace the grease, preferably with a more viscous one. - Clogged oil filter... As a result, the oil does not reach the hydraulic lifters under the required pressure. Therefore, an air lock forms, which is the cause of the problem.
What to do - replace oil filter. - Oil level mismatch... It can be either a reduced or an increased level. The result is excessive air saturation of the oil. And when the oil is oversaturated with an air mixture, a corresponding knock occurs.
How to check the hydraulic lifter
What to do- the solution to this problem is oil level normalization. - Incorrect operation of the oil pump... If it does not work at full capacity, then this may be the natural cause of the indicated problem.
What to do- check and adjust the oil pump. - Increased seat of the hydraulic compensator... As the engine heats up, its volume increases even more, which is the reason for the knock.
What to do- for help contact the mechanic. - Mechanical and hydraulic problems.
What to do- there can be many reasons here, therefore we recommend contacting a specialist.
Hydraulic lifters knock on cold
Now let's list the list of possible causes that cause the knock of hydraulic lifters on a cold engine and what to do about it.
