Hello, today I wanted to talk about such a malfunction as the knock of hydraulic lifters, let's get it in order, first let's figure out what it is and what is it responsible for?

So, hydraulic lifters are installed in modern engines and they are designed to automatically adjust the thermal clearances of the engine valves. This is achieved by finding special springs in them and the oil that is supplied to them.

So, hydraulic lifters automatically adjust the valve clearance. I think many remember that on old engines, for example VAZ 2106, there are no hydraulic lifters, there the valve had to be adjusted manually.

What happens when the valve clearance decreases or increases?

The engine starts to work poorly (in simple terms). Power decreases, fuel consumption increases, sometimes the internal combustion engine starts to work unevenly. These are the main problems.

So, so that we do not have to manually adjust the valves, hydraulic lifters were installed in the internal combustion engine. They are arranged in essence simply and there is especially nothing to break there, but! For several reasons, they still fail and we always hear it!

There are several stages, the most common: when starting the engine after a long stay, a metallic knock is clearly audible, as if many metal nuts or bolts are knocking on metal. After a while, the knocking goes away. This is due to the heating of the engine. Compensators collect oil and stop knocking.

The next stage. The knock disappears, but when the car is idling, the knock resumes, only when the car is in motion. This is due to the fact that at idle, low oil pressure, the hydraulic lifters do not have enough oil and they knock.

And the last one - the knock does not go away at all. Please note that if they knock, it does not mean that they do not fulfill their functions at all, they just do it badly, but they do! Therefore, the car can continue to drive well enough.

Disassembled hydraulic compensator

So, the first two stages do not threaten the engine with anything yet, but someday they will definitely go to the third stage! Therefore, let's talk about her, and what to do to prevent this from happening.

The most dangerous thing that can happen and someday will happen if nothing is done, the hydraulic lifter will jam.

I forgot to mention that let's say there are 16 hydraulic lifters in a 16 valve machine. Everyone works independently. The valve will stop working normally, it can jam, or vice versa, make a huge gap. If one hydraulic lifter jams, you may not even notice it, a few will jam, the car may, in principle, not start, and if it starts it will work very badly. In Russian, "troit"

For what reason do they fail? There are actually a lot of reasons, let me name the most popular ones.

Poor engine oil.

The oil filter inside the internal combustion engine is clogged, respectively, the oil pressure in the system is low.

The hydraulic compensator itself is mechanically faulty. Inside it there is a plunger pair installed, which inevitably wears out over time.

Dirty hydraulic lifters.

So let's try to solve the problem.

To do this, first of all change the engine oil, and if you are pouring cheap oil, buy a good one, very often at this stage the problem is solved!

Remember to flush the engine and change the oil filter. Rinse like this: Drain the old oil, fill in the new one, let the car run for 5-7 minutes, drain this oil and leave it in the gravy, then fill in the new one again.

If this does not help, you need to disassemble, remove and flush the hydraulic lifters, but before that, check the oil pressure in the system at the service station. If they are low, this is very likely the reason.

Hydraulic compensator in the internal combustion engine

If you are able to disassemble the internal combustion engine yourself and remove the hydraulic lifters, then I advise you simply with the help of specials. funds (sold in auto stores) rinse and collect them.

If you give a car for repair, then it is advisable to completely replace them with new ones, you still have to pay for the work so that you do not have to pay twice, if flushing does not help, it is better to immediately new ones, while asking and best of all check that the engine inside is washed from mud.

The knock itself occurs when there is simply not enough oil in the hydraulic lifter, or it is not of high quality.

And the last reason for knocking is wear of the hydraulic lifters' seats, this will already lead to serious engine repairs, but this problem does not occur very often, so do not worry about earlier.

Now you know what threatens the knock of hydraulic lifters, and how you can fix it yourself!

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 the 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, no wear or seizure.

How to understand what the hydraulic lifter is knocking

A faulty hydraulic compensator emits a sharp knock, chirp, with a frequency of half the engine speed.

A hydraulic lifter is considered 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 on top of 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):

1. Too thick oil, on a cold engine, does not fit well into the cavity of the hydraulic lifter. It takes time for the cavity to fill with oil
2. Clogged oil line or hydraulic compensator valve... Contamination appears when the quality is low or when the engine oil change period is prolonged, and can also be products of wear of some engine parts.
3. Worn or seized hydraulic lifter plunger. It happens from normal wear and tear or from the ingress of abrasive contaminants into the engine oil.

The reasons for the knock of the hydraulic compensator "hot" (on a warm engine):

1. Jamming of the hydraulic compensator plunger pairdue to normal wear and tear or dirt. Seizure marks on the plunger block its movement and the hydraulic compensator completely loses its performance. The gap is not selected and the hydraulic compensator knocks.
2. 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 stirring by the crankshaft or due to water entering the engine. The engine oil level should be checked and only high quality engine oils should be used.

The easiest way to eliminate the knock 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 washes 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

1. 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.
2. 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 linesthe 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 drop 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 hydraulic lifters repeatedly occurs, then there is no point in waiting for the situation to worsen. Adding an additive will solve the problem and prevent wear from developing for a long time.

VIDEO

;

Let's immediately determine that the knock of the hydraulic lifter is a problem that occurs in 90% of cases not on new cars, although exceptions are possible if a low-quality part was installed at the factory. But this is also unlikely, since the hydraulic lifter belongs to the power unit, and factories that produce engines have much more stringent requirements with regard to the quality of the components supplied by suppliers.

Problems with the knock of hydraulic lifters over time can occur on a car of any make, year and country of manufacture.

There are also a lot of options for the manifestation of a malfunction - on a cold engine, on a warm one (as they say, "hydraulic lifters knock on cold or hot" - respectively), standing still and while driving.

There are a number of ways to eliminate annoying sound, each of which should be used in a specific situation.

But in order to understand why the hydraulic compensator knocks and the reason for its failure, you first need to figure out what kind of mechanism it is, what it consists of, and how it functions. And in general, what can such a knock lead to, and what will happen if it is not eliminated in a timely manner.

The hydraulic compensator of the car - just about complicated!

In order to understand the principle of operation of the hydraulic compensator, and therefore to determine why it fails and how to repair it, one must remember the engine design. Remember how the valves are located and what are they for? The inlet valve is responsible for the fuel supply, and the exhaust valve is responsible for the exit of gases spent during fuel combustion in the engine.

So, the hydraulic compensator is a device that automatically adjusts the valve clearance, thus, providing a uniform supply of fuel to the engine working chamber and the output of "working off". The installation of hydraulic lifters makes it possible to exclude the process of manual valve adjustment for the manufacturer's servicemen, which, by the way, is very laborious and time-consuming.

Why do hydraulic lifters knock?

Now let's get down to the question of where the very unpleasant knock from under the hood of your car comes from.

There are usually two common reasons:

1. Knocking occurs due to damage or destruction of the mechanical parts of the hydraulic compensator itself.
2. Knocking occurs due to a malfunction of the systems supplying oil to the engine.

Professionals even know how to identify a knocking hydraulic compensator by ear, and what exactly is the problem.

The reasons for the destruction of the mechanisms of the hydraulic compensator itself include the depletion of the resource of the plunger pair installed inside the hydraulic compensator. This happens over time, unfortunately, this process is inevitable, therefore, replacing hydraulic lifters should be treated as replacing any automobile "consumable". Depending on the quality of the components used in the production of the hydraulic compensator, its service life directly depends. The lower the quality of the metal, the faster it will fail. Naturally, a factory defect can also take place. Also, the hydraulic compensator is damaged if air enters it, or too little oil, or due to contamination of the parts of the hydraulic compensator. There are many reasons, but the result does not change from this - the mechanism fails and requires either cleaning if you diagnosed the problem at an early stage, or a complete replacement, if at a later stage.

With regards to the violation of the oil supply to the engine. A knock will occur if the oil level in the engine differs from the norm, both in a lower and a higher direction. End of life and failure of the oil filter. Contamination or ingestion of carbon deposits formed during engine operation into the oil channels.

Choosing the wrong brand of oil. Naturally, if you overheat the engine, then the physical properties of the oil will change, which will also lead to a malfunction of the oil supply systems.

We have already said above that knocking can occur both with a cold and with a warm engine.

On a hot engine, the presence of knocking is most likely due to the presence of oil in the engine, which is high time to change, or if you have done this recently, it means that you have come across an oil of inadequate quality - this, by the way, is another reason to buy lubricants only from official representations or dealers. Filling with low-quality oil can cause engine damage much more serious than the clatter of hydraulic lifters.

It often happens that replacing the oil with a new one solves the problem with the knock of the hydraulic lifters.

If you have not changed the oil filter for a long time, then be sure to replace it, or at least clean it, for which you should use a special hydraulic lifters cleaner.

Although, according to the regulations for car maintenance, the oil filter is supposed to be changed simultaneously with the oil change.

If the performance of all the above operations did not give any result, you should consider other options for the occurrence of knocking in the engine compartment, since replacing the filter and using high-quality engine lubrication in 90% of cases helps to solve the problem. Remember that knocking under the hood with a warm engine is a critical indicator and requires urgent intervention and elimination of the cause of its occurrence.

And vice versa, if your hydraulic lifters knock on a still cold car - it doesn't really matter. Cold oil has physical characteristics different from hot oil and does not get inside the hydraulic lifter, so you just need to wait for the engine to warm up. If the knocking persists, then you should start solving the problem.

Which hydraulic lifter is making a knock?

To determine which of the hydraulic lifters is making a knock (usually their number is equal to the number of valves in your engine), use the “by ear” diagnostic technique, while using a technological type of medical device such as a phonendoscope - you almost certainly saw it on your therapist's neck.

It is this device that allows the master to say exactly where the source of the knock lies, although real pros, of course, will determine this without any phonendoscope.

After diagnosing a knocking part, it is required to remove the hydraulic lifter, thoroughly clean it, then reinstall it and start the engine again.

If the knocking persists, the hydraulic compensator is considered to be out of order, and the service will replace it.

If the knocking persists even after replacement, then the reason most likely lies in the quality of the oil used, or in other engine components. The latter is unlikely, since diagnosing a sound source using a phonendoscope is an accurate procedure and, as a rule, does not fail.

Consequences of inaction when knocking hydraulic lifters

If the knock is really emitted by hydraulic lifters, untimely replacement, or repair of hydraulic lifters will lead to a reduction in the service life of the gas distribution mechanism drive and the cylinder head.

Repair of both the first and the second unit is an expensive and burdensome pleasure.

And finally, let's say that you can, of course, both diagnose the problem on your own, and also fix it yourself.

But flushing or replacing hydraulic lifters is already a direct intervention in the systems of the power unit of your car, so if you feel the slightest doubts about your abilities, take the trouble to contact an authorized service center.

If you "screw up", then you still need to contact the "officials", and they will certainly determine that someone has already looked under the valve cover before them, because even checking the hydraulic lifters requires opening the valve cover and turning the crankshaft manually.

In the most negative scenario, you will not only pay for expensive repairs to the power unit or timing drive, but will also be removed from warranty service (if your car is still covered by the warranty).

Any risk must be justified, and replacing hydraulic lifters is not a problem that is solved in the middle of a motorway in the absence of spare parts and necessary tools. Think 10 times whether it is worth taking on such work on your own, or it is better to entrust it to professionals.

Timely identification of the problem and simple operations to eliminate it, even if you contact the service, is the key to saving your money and the resource of the machine's power unit.

How to determine the malfunction of hydraulic lifters?

For normal operation of the motor, constant adjustment of the clearances in the cylinders is required. In order for this adjustment to be carried out in automatic mode, it is necessary to monitor the performance of the hydraulic lifters. It is these seemingly simple elements of the motor that are responsible for adjusting the clearances in the valve drive mechanism. How do you know if there are hydraulic lifters in your motor? Today we will list the main “symptoms” in order to recognize the problem in advance.

The main sign of failure is the presence of extraneous noise when the motor is running. Extraneous knocking occurs immediately after starting the engine. Depending on the engine speed, the sound will change. Extraneous knocking comes from under the valve cover. However, if there is an extraneous knock in the motor, but it does not change depending on the speed or does not appear immediately, then the cause of this knock is not at all hydraulic compensators.

The launch of various consumers and additional elements such as air conditioning or high beam should not affect the sound from under the hood in any way. The knock may decrease or disappear completely as the engine warms up. This means that the hydraulic lifters are dirty. They need to be rinsed, as well as to replace the engine oil, it is this oil that contaminates the "hydraulics" and adds noise to the engine.

Having identified that the cause of extraneous knocking are hydraulic compensators, it remains only to check which element is out of order.

To check the hydraulic lifters on the intake valves, the following procedure must be performed:

1. Remove the valve cover from the engine immediately after stopping the engine.

2. Turn the engine crankshaft so that the piston of the first cylinder is at top dead center during the compression stroke.

3. Press on the shoulders of the intake valve rocker

If you can easily turn the rocker when pressed, then this is a sign that the unit is out of order.

To check the exhaust valve lifters, you will need to use a different method:

1. Crank the crankshaft slowly until the exhaust valves begin to open.

2. Watch the poppets of both valves

3. If the hydraulic compensator is faulty, the disc spring will move unevenly, with a delay relative to the second valve.

This method is not suitable for DOHC motors. To diagnose it, you will need to apply force when trying to move the lever that rests on the hydraulic compensator. A serviceable element should not succumb to you, but if it is easy enough to move it, then you should think about replacing the hydraulic lifters.

We apply the verification method to all hydraulic lifters in your motor.

Before changing the hydraulic lifters, it is worth trying to clean the old ones and this can help fix the problem with this motor. If cleaning did not help, then all that remains is to replace the faulty unit.