If the engine consumes an increased amount of oil and smokes when you press the gas pedal, then you should prepare to replace the valve stem seals. Let's talk about when they should be changed and what signs of wear.

signs of wear

Let's explain why caps are needed. Their purpose is to keep excess engine oil out. They should fit snugly against the valve and allow only the small amount of oil needed for lubrication to pass through. Made from a special rubber that is not afraid high temperatures.

Over time, the valve stem seal begins to break down, rubber ages, loses elasticity and peel off from the base. It starts leaking oil. Consequently, the consumption of engine oil is increasing. As a rule, on domestic cars, the replacement interval is 80,000 kilometers. For modern motors this period can be increased by 2-3 times due to the use of modern materials and good engine oil. These conditions are relevant, unless there is an overheating of the engine or oil starvation.

Does the car engine have an increased oil appetite? Does the engine consume more than 1 liter per 1000 kilometers? Is there blue smoke coming out of the exhaust pipe? These are the first signs of wear on the valve stem seals. Of course, you can not think about a major overhaul if you have not decreased dynamic characteristics and no increase in fuel consumption.

These problems can be solved by replacing the caps and do it yourself. You will need a garage and a repair tool - the most necessary is a valve cracker puller. You can find it at an auto tool store.

Video instruction

We will not go into the procedure for replacing engine caps. Detailed operation can be found in technical guidance for repair. In addition, everything is explained there in an accessible, thorough and with pictures. For example, a video showing the replacement process is the easiest way.

To complete the work, you will need special tool- a device for "drying out" the valves. Execute without it this work fail. On the Internet you can find drawings and make your own. It's easier to buy a ready-made tool in a car shop.

The great danger of replacing caps lies in wait when trying to “dry out” the valves. For this purpose, there is a special device, one end of which is fixedly attached, and the other - presses on the plate, while compressing the valve return spring. Then you should remove the "crackers" from the valve. It is better to do this with a magnetic screwdriver or long tongs. be careful, if you lose the "cracker", then the reassembly process will be impossible. In practice, these small "crackers" can fly out in an unknown direction, and then it is difficult to find them.

Also, you need to close all the holes on the engine with foam rubber so that “cracker” or dirt does not get there. When installing a new cap, do not forget to pre-lubricate it with engine oil.

The operation to change worn valve stem seals can be done independently, but experience and tools are required. If there is no knowledge, then it is better not to take up the matter. The price is not high, so entrust this operation to the masters.

Structurally in the engine internal combustion There are several types of seals that serve as seals for various movable joints, among which a special role is given to valve seals or, as they are also called, valve stem seals.

Purpose

Protection of the combustion chamber from oil ingress from the cylinder head.
Oil is supplied to the block head under pressure for lubrication camshafts, during rotation of which an oil mist is created in the cavity of the head, consisting of splashes of hot oil deposited on all elements of the head of the block.

Where are they?

Guide bushings for inlet and exhaust valves. A certain thermal gap is left between the sleeve and the valve stem, designed to expand the parts when heated.
In order to prevent oil from the block head from entering the combustion chamber through this gap on the bushings, oil seals are installed in the form of caps, for which they got their name - “valve seals”.

Device

The gland is a steel cylinder for a hard fit on the head of the guide bushing. On top of the cylinder, a layer of rubber or rubber (fluorine or acrylate rubber) is vulcanized in the form of a truncated cone, to tightly wrap around the valve stem and remove oil during its working stroke. A spring ring is installed at the end of the cap for reliable contact of the cap with the valve body.

When do you need to change?

At work power plant, depending on the engine speed, every minute the valves perform about 200-1200 cycles, which negatively affects the resource of the caps, causing their natural wear.
Car manufacturers do not give any data on the frequency of replacing valve seals and this work is carried out as signs of their malfunction are detected.

Symptoms of a malfunction:

Oil on the threads of candles, with severe wear of the caps, oil is already present on their electrodes;

Power drop, deterioration in dynamics and increase in fuel consumption;

Unstable start of a hot engine;

With an engine, it is the caps that are the first to suffer, as they are the most highly located in the engine, plus those in contact with the valves heated in the combustion chamber. In such cases, the seals simply "tan" and are no longer able to do their job, allowing the oil to freely enter the combustion chamber.

A seal failure can also be detected when the valve cover is opened to perform adjustment work or replace the gasket. This applies to engines where caps can be seen. The malfunction will be expressed in the absence of a spring, or an oil seal that has “removed” from the guide sleeve and “sits” on the valve stem.

How is the replacement process going?

On many engines, valve stem seals are replaced without removing the cylinder head, only partially disassembling it to get to the oil seals.

However, if the engine has been running for a long time with faulty caps, then this definitely led to the formation of carbon deposits on the plates and valve seats, which must be removed in order to reliable operation engine.

Moreover, in most cases removed head it is found that its plane is not parallel, which must be milled.

In any case, this work belongs to the category of complex and responsible and must be carried out in a car service, or in the garage of an experienced mechanic, where there are all conditions and essential tool to carry it out.

However, there is a nuance here. Replacement will only be advisable if the valve stem bushings are not worn. Otherwise, the service life of new parts will be extremely limited and repeated repairs will be required.

The fact is that if the valve stem runs in a guide with a large gap, then it will not move in the center of the sleeve, but with a warp and constantly press on one edge of the cap, causing its intense wear.

What happens if it's not repaired?

As follows from the theory, for the combustion of 1 liter of gasoline, 14-16 kg of air is needed and such air-fuel mixture will be the most favorable for the operation of the engine, both in terms of fuel economy and full power output.

When oil appears in the composition of this mixture, this leads to its incomplete combustion, precarious work engine, loss of power and increased fuel consumption.

In addition, during the combustion of oil, carbon deposits form on the valve plates, piston crown and spark plug electrodes. With a strong flow of oil, when the caps are no longer able to hold it, misfires appear, or one of them stops working altogether.

Soot on the valves - one of the consequences of faulty caps

The soot that appeared on the valve plates does not allow them to tightly “sit down” in the valve seats, which leads to a decrease in compression in the cylinders and interruptions in the operation of the power plant. Plus, a loose valve seat (especially exhaust valves) creates conditions for a breakthrough of hot gases from the combustion chamber and burnout of the valve disc.

If the above listed malfunctions are found, it is recommended, without postponing for a saving tomorrow, to contact car service professionals to extend the engine life.

Engines modern cars have in their design a lot of very small, but very important details for its proper functioning. If you do not find out in time that they have become unusable and do not take appropriate measures, then the consequences of this for power unit, and, accordingly, the budget and nerves of a motorist can be the saddest. These "little things" include valve stem seals.

They are part of the design of the gas distribution mechanism (timing) of a car's internal combustion engine. Their dimensions are quite small and they are by no means located in plain sight, but inside the engine.

As you might understand, this article will be devoted to valve stem seals. Here you will learn why valve stem seals are needed and what are the signs of wear.

Valve and valve stem seals.

Valve stem seals needed in engines to keep oil and debris out of the combustion chambers. They are often called valve seals, and this name fully reflects the role they perform.

Valve stem seals are located directly on the valve stems, and consist of three main parts:

• Base;
• Actually cap;
• Spring.

The base is a sleeve made of steel. It plays the role of the frame of this part and gives it the necessary strength. The cap itself is the main element of the part. It is made from a special rubber resistant to high temperatures and friction forces. The cap is mounted inside the sleeve, and when mounted on the valve, fits snugly around the stem and removes oil. And the spring is mounted in a special annular recess of the cap and ensures its tightest fit to the stem.

As for the oil that these caps must remove, it is supplied to the gas distribution mechanism oil pump. It is designed to lubricate timing parts that experience friction and increase their resource. At the same time, its penetration into the cylinders through the valve groups is highly undesirable, since, when burned, it forms carbon deposits that accumulate on their walls.

It should be noted that in modern engines Internal combustion valve stem seals have to function in rather harsh conditions of high temperatures and increased mechanical loads. In addition, they are also negatively affected by the substances contained in the removed lubricating fluid. Therefore, manufacturers of valve stem seals use the most durable materials that are resistant to friction, thermal and chemical effects for their manufacture.

Wear of valve stem seals

Like any other part of an internal combustion engine, which regularly experiences a whole combination of negative effects of various kinds, valve stem seals gradually but steadily wear out. Their most loaded rubber part loses elasticity over time, cracks appear in it. In addition, over time and under the influence of high temperatures, the clamping force of the spring inevitably weakens. As a result, the wear of the valve stem seals leads to the fact that the oil is not removed from the valve stems and it enters the combustion chamber of the internal combustion engine.

As practice shows, the resource of valve stem seals installed in modern internal combustion engines is approximately 100,000 kilometers. After the car has passed this distance, they must be replaced. Experts also recommend changing valve stem seals in car engines that have been out of service for a long time.

In addition, it often happens that valve stem seals wear out prematurely for one reason or another. In such cases, they, of course, also require replacement with new ones. The fact that the time for this kind of engine repair has come is evidenced by several characteristic signs.

signs of wear

Valve stem seals.

The following signs may indicate wear on the valve stem seals:

• Significantly increased oil consumption;
• The appearance of soot on the electrodes of spark plugs;
• Appearance exhaust gases blue when the engine warms up.

The increase in the "oil appetite" of the engine when the valve stem seals are worn is quite logical and understandable. The point is that that lubricating fluid, which is not removed by them from the valve stems, enters the cylinders and burns out. Accordingly, it is irretrievably lost from the lubrication system of the power unit, and the oil has to be topped up more often than usual.

Since the oil burns, the combustion products that have Blue colour, come out, painting in the appropriate color traffic fumes. When the engine warms up, the oil burns out almost completely, so blue smoke disappears.

In addition, if the oil is not capped, gets into the cylinders, then its smallest drops also settle on the electrodes of the spark plugs. Accordingly, after combustion, carbon deposits form on them.

Consequences of wear of valve stem seals

As soon as the listed signs of wear of the valve stem seals begin to appear, you should check the gas distribution system of the car, and Special attention it is necessary to pay attention to the valve stem seals. Experienced motorists do it on their own, less sophisticated go to the station Maintenance where the diagnosis is made by experienced specialists.

It should be noted that it is strongly not recommended to operate the engine with worn valve stem seals. As practice shows, if you ignore this defect and do not eliminate it, then it is almost inevitable:

• The power of the power unit will decrease;
• On Idling it will start to stall periodically;
• Turnovers will "float";
• Compression will drop significantly;
• On cylinders, pistons and valve seats soot will appear.

As for soot, its appearance is indeed a very serious "bell", since its formation may well lead to a very expensive overhaul of the power unit.

In the design of any engine, and domestic car, and foreign cars, there are valve stem seals (valve seals).

They are always involved when the machine is running, and therefore wear out very quickly. Increasing their service life headache engineers working on automobile factories, but the timely diagnosis of signs of wear of valve stem seals, as well as their replacement, is already the task of motorists. You can successfully deal with it only in one case, when these very signs are known to you, and if not, then this article will help you.

How do valve stem seals work and when are they considered worn out?

As you know, the valve in the engine is located in two different cavities. One of them implies the presence of engine oil in it, the other, on the contrary, must be isolated from it. In this case, the valve during its operation is in constant motion. In order to maintain the tightness of the hole through which it moves from one medium to another, valve stem seals are just what is needed. They are made of special elastic rubber, however, this rubber tends to age, harden, dry out and collapse over time, as a result, the caps no longer cope with their task and begin to need to be replaced. car owner this moment can be identified by specific features.

The main signs of wear of valve stem seals.

1. Increased oil consumption - if engine oil more is consumed in your car than it should be, which means that somewhere it is used in vain, as an option, it enters the combustion chamber due to worn valve seals.
2. Oily - a consequence of the fact that oil enters the cylinders.
3. when the car warms up, the engine heats up - the smoke disappears. Such a phenomenon is clear sign a cracked cap, which, when heated to a certain temperature, becomes wider and begins to successfully cope with the functions assigned to it again.

However, be extremely careful, these signs may indicate not only worn valve stem seals, but also other problems with the engine! Therefore, at the time of diagnosis, do not forget to pay attention to:

• mileage - as a rule, oil seals need to be replaced every 70-80 thousand km. run;
• - if it is reduced, but you did not find any leaks or problems with the valves and / or rings on the pistons, then the problem is definitely in the caps. They should be replaced.

Consequences of driving with worn valve stem seals.

If you missed the moment of failure of the valve seals, then most likely it will lead to the following consequences:

• increased oil consumption, which, firstly, does not in the best way will affect your budget, and secondly, it will provoke periodic oil starvation leading to increased wear details and the need for premature overhaul engine;
• oiliness and eventually failure of spark plugs;
• valve burnout - soot will form wherever there is oil, including on the walls of the cylinders, which over time will interfere with the closing of the valves and lead to their burnout.

To prevent all this from happening, timely replacement as soon as you notice the first signs of wear on the valve stem seals.

We will not consider the procedure for replacing valve stem seals now, this is the topic of a separate article, but in the end we will name the main recommendations that will save you from mistakes. There are only 3 of them:

1. to crack the valves, always use a special tool - a cracker, so you will be less likely to break or lose something;
2. when changing caps, cover all holes on the engine with a rag or foam rubber, they will protect open cavities from dirt, and you from losing crackers;
3. Be sure to lubricate the new cap with oil before installing.

And remember, if you do not have enough experience and knowledge in replacing valve seals, if you notice signs of wear, do not experiment, but give your car into the hands of professionals, they will quickly replace the failed parts with new ones and take them into this case A little. Depending on the car and the service station, the costs will range from 7 to 20 thousand rubles.

Video.

Valve stem seals or valve seals prevent oil from entering the combustion chamber through the valves. How many of them in the engine can be determined by the number of valves: 12 valves = 12 caps.

The valve stem seals are located directly on the valves. This rubber product is a consumable item and must be replaced periodically.

MSC location on 7a-fe

When to change

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like anyone consumable, caps require regular replacement. Masters advise changing the MSC every 50-70 thousand kilometers. This will avoid serious problems with a motor.

How to check the status? To the touch. If the seal is hard, it's time to change it.

Obvious signs of MSC wear:

• increased oil consumption;
• blue smoke from exhaust pipe after starting the engine. Signals about the ingress of oil in the cylinder and its combustion;
• the appearance of oil on the threads of candles.

The first symptoms of wear indicate the need urgent replacement MSC.

Replacement

You can change the valve stem seals yourself or at the service. If you have experience in repair Toyota cars And right tool you can replace it yourself.

In order to remove MSCs, you need a special tool called "valve cracker" and cap remover.

Which caps to choose is up to you. Now you can buy valve stem seals online at bargain prices. But it is better to purchase high-quality consumables so that you do not have to change them ahead of time. The main parameter for MSCs is their compliance with your Toyota models. The price starts from 60 rubles apiece, depending on the engine model.

Installing valve stem seals with your own hands is not a difficult procedure, but it requires care and experience. During valve cracking, there is a danger of losing the cracker. After that, it will be impossible to assemble the motor back. You should also pay attention to protecting the engine from dirt during replacement. If you are not confident in your abilities, do not take it.

Example: replacing valve stem seals with 1zz-fe

How much does it cost to replace valve stem seals on your own and in the service, let's look at an example. Self-replacement Requires tools and supplies.

Universal cracker - 850 rubles.

Oil scraper caps - 120 rubles * 16 pieces.

Puller - 200 rubles.

Repair will take a simple motorist at least half a day. Total: 2970 rubles. How to replace valve stem seals is described in detail in each vehicle manual. Toyota owners willingly share photos of their experiences in replacing MSCs.

The cost of replacing the service is from 1500 to 3000 rubles. Plus the caps themselves - about 2000 rubles. Total maximum 5000 rubles and 40 minutes of waiting.

Obviously, the replacement at the service is more expensive, but it also takes less time. In addition, a motor mechanic will cope with this task better than a simple car owner.

Additives for MSC

To avoid replacing consumables or delay it, you can use special additives. The additive for valve stem seals is designed to soften them, that is, to increase the service life of already worn MSCs. There are sealing additives that fill the gaps formed by time through which the oil passes.

Autochemistry of this kind is very popular due to its low cost compared to replacing MSCs. In addition, additives act on all rubber products, extending their service life.

How to check if the additive is working? If you have already used specialized auto chemicals, keep an eye on oil consumption. If it fell, the additive is effective. best manufacturer automotive additives counts american brand Wagner.

followed by German Liqui Moly.

Many motorists use domestic additives laurel.

MSC replacement is much more efficient than additives. In the end, the seals will still have to be changed. In order not to harm the engine, contact a specialist.