Engine lubrication system internal combustion similar to the human circulatory system. Oil, like blood, circulates in a vicious circle, lubricating, cooling and cleaning moving parts. All this, of course, occurs under a certain pressure, the decrease or excess of which will invariably lead to disruption of the workflow.

The slightest oil leak from the engine is a signal that a system depressurization has occurred. And this is a serious reason to think about diagnosing the power unit.

In this article, we will talk about why it occurs, and how to eliminate oil leakage from under valve cover.

What is a valve cover

This element of the internal combustion engine is designed to protect it from dirt, dust and moisture. In addition, the lid protects everything engine compartment from oil, which is supplied under pressure to lubricate the timing.

The first internal combustion engines did not have a valve cover, because of which they constantly had to be washed and cleaned. Over time, the timing began to be covered with stamped covers made of thin sheet steel. Today, this element is made of aluminum by casting. And this is no longer just a cover, but a whole structure, the task of which is to protect the timing, and participate in the crankcase ventilation process, and collect the oil sprayed by the moving parts of the gas distribution mechanism.

In order to ensure tightness, the valve cover is attached to the cylinder head through a rubber or silicone gasket. In some new cars, the gasket is not installed at all: its role is played by a layer of special sealant.

Possible Leak Locations

If you notice that oil is leaking from under, try to pinpoint the exact location of the leak. Most often, grease can leak:

In rare cases, an oil leak can also occur on the cover body itself. This may be due to mechanical damage or manufacturing defects during casting.

Causes of oil leakage from under the valve cover

Oil leakage from under the valve cover can be due to two factors:

• loss of the gasket of its sealing properties;
• increasing oil pressure in the system.

In the first case, the gasket, due to the significant operating time and the influence of high temperature, simply coarsens or cracks, which cannot but affect the tightness of the system. This is not the worst case. It is enough to change the old gasket to a new one, and the tightness will be restored.

But if oil leaks from under the valve cover are caused by an increase in pressure inside the system, further diagnostics will be required. And you need to start it with a pressure measurement.

How to measure oil pressure

As already mentioned, the lubricant circulates through special channels inside the engine under pressure created by the oil pump. The normal oil pressure for each engine is different, it all depends on its volume, number of cylinders, valves, etc. In order not to guess, look in the owner's manual for your car, everything is indicated there. So, if the pressure in the system decreases, its sensor will instantly signal you about this with a lamp that lights up on the instrument panel.

If there is an increase in him, he will not react in any way. In other words, high pressure can only be detected by connecting a special liquid pressure gauge to the engine instead of a sensor. Focusing on its readings, we can conclude that oil is flowing from under the valve cover due to an increase in pressure in the system, or the reason is still in the gasket (seals).

What does high oil pressure mean?

For a car, as well as for a person, "hypertension" does not bode well. In our case, it is evidence of a malfunction in the lubrication system. So, if oil is leaking from under the valve cover in your car, and you have diagnosed an increase in its pressure, the reason for this may be:

• violation of normal crankcase ventilation due to clogging of the oil separator screens;
• clogging of the oil channels of the cylinder head;
• blockage oil filter;
• jamming pressure reducing valve in the closed position.

Let's consider these reasons in more detail, and in the order in which it is better to diagnose: from the simplest to the complex.

Violation of normal crankcase ventilation

Let's start with the most common cause of increased pressure in the lubrication system, found in domestic cars. Most often, oil from under the VAZ valve cover begins to ooze due to a violation of crankcase ventilation. Simply put, crankcase gases, which should be free to exit the engine, encounter obstacles in their path and begin to accumulate inside, creating excess pressure. In this case, it not only presses oil from under the valve cover, but can also throw it out through the breather into the air filter housing.

What could these obstacles be? Firstly, the oil separator mesh, if it is clogged with combustion products. And secondly, the usual deposits and dirt on the inner walls of the fittings to which the ventilation hoses are attached. So, if oil is driving from under the valve cover in our car, do not be too lazy to remove the valve cover and rinse the oil separator mesh, and at the same time clean the fittings.

Clogged oil channels and filter

It has a whole network of special channels through which oil moves. The use of low-quality lubricants, dirt entering the system, engine overheating are the main reasons why these channels can become clogged. When this happens, the oil pressure naturally increases as the oil pump continues to run.

The same thing happens when the filter is clogged. It loses its capacity, creating increased pressure in the system. And it is not surprising that oil flows from under the valve cover if you changed the filter several years ago.

Eliminated this problem by replacing the filter element and flushing the system using special fluids.

Pressure reducing valve failure

Often, an increase in oil pressure is a consequence of a malfunction of the oil pump, because it regulates it. The most common cause of a malfunction is jamming in the closed position, caused by friction products (fine chips) or dirt getting into its mechanism. Getting rid of such a problem is easy. The valve is easy to disassemble and clean, however, this will require dismantling the oil pump.

Choosing a valve cover gasket

Pay enough attention to the choice of gasket, since you are unlikely to be able to eliminate oil leaks from under the valve cover using a low-quality product. It's better to give preference here. original spare part by recognizing its factory catalog number. If the design provides for a rubber gasket, make sure that the rubber is soft and does not have any cracks or sagging. All these defects will definitely affect the tightness.

Do I need to lubricate the rubber gasket with sealant?

As for the use of sealant, the opinions of auto mechanics differ. Some consider its use unacceptable, while others, on the contrary, argue that only with it can complete tightness be achieved. Let's just say that if the surfaces of the cover and cylinder block are rough, the use of sealant is desirable, but only if it is applied in a neat thin layer. If the surfaces are perfectly even, you can do without it, because a few years ago no one really used such a sealant. Well, for cars where the gasket is not provided for by the design, sealant is indispensable.

If oil leaks from the neck or at the bolted joints

It happens that oil does not flow from the junction of the mating surfaces of the cylinder head and valve covers, but, for example, from the oil filler neck or where there is a bolted connection. The cause of such leaks is the same excess pressure. Having eliminated the causes of increased pressure, it is recommended to replace the rubber seals of the bolts (if they are provided for by the design), and also check the tightness of the oil filler cap.

Finally, here are a few useful tips, which will allow you to avoid problems with oil leakage or deal with them faster.

1. Timely change the engine oil, as well as the oil filter.
2. Use only quality lubricant.
3. Keep dirt, water, and other process fluids out of the lubrication system.
4. When passing maintenance, do not forget to check the oil pressure in the lubrication system. In case of detection of its increase, immediately repair the car.
5. Do not overheat the engine.
6. Check the operation of the components responsible for crankcase ventilation.
7. When choosing a valve cover gasket, give preference to the original product.
8. Apply the sealant to the gasket in a thin, continuous layer. Do not let it get on the elements of the gas distribution mechanism.
9. When screwing the valve cover, do not overtighten the bolts.
10. If you find an oil leak from under the valve cover, do not delay with diagnostics and repairs.

Hello, dear readers and visitors of the blog. In the article, you can find out the causes of oil leakage in a car engine without contacting the station specialists. technical inspection. The knowledge gained will be needed by drivers who actively use the car. It is not always possible to turn to specialists for help and you must independently find and eliminate the causes of oil leakage in the engine.

An oil leak in the engine is a malfunction signal. Like blood from a wound on a human body. There was a weak point in the motor. Requires discovery and conduct.

Ignoring an oil leak is fraught with serious problems in the operation of the motor. At an early stage, an oil leak can be fixed without significant material costs. Running cases painfully "hit" the pocket of the motorist.

At the end of the article, you can find a video demonstrating the causes of oil leaks in the engine. It will be an excellent addition to the text material.

The motor drives the wheels of the car. There is a displacement vehicle. A modern type engine is a complex multicomponent system.

Requires regular and timely maintenance. increases during work. Between work items power plant active friction occurs.

The main task of the used engine oil is to reduce friction between the individual engine components to a minimum level and ensure the removal of deposits, soot, and metal particles that form during operation.

Oil performs another important function - protecting the motor from overheating. The circulation of the oil ensures an optimal level of heat exchange between the power plant and the environment.

Leaks are dangerous because the oil level in the engine decreases. Insufficient level leads to increased wear of the motor elements. The resource is declining. Inaction is fraught with failure of individual working parts of the motor.

It is important to follow and look under the car. Otherwise, it is impossible to detect and eliminate the leak in a timely manner. Oil leakage worsens appearance motor. Like a magnet attracts dirt, sand and dust. Strong engine oil can provoke.

There can be several reasons for oil leakage. Troubleshooting is difficult because engine compartment it is impossible to stick out the palm. Everything is set tightly. It is impossible to detect a malfunction due to limited visibility.

Causes of oil leakage:

1. Oil spill.

Replacement drivers motor oil with their own hands, allow overflow. Overpressure builds up inside the motor. Not designed for this amount of lubricant.

Excess oil is looking for a way out. Overflow degrades the quality of the power plant. If an overflow occurs, the excess fluid is drained to normalize the pressure.

2. Violated crankcase ventilation.

Or in the common people, the pan serves to store oil. In engines that have been in operation for 10 years or more, piston ring wear occurs. There is a hit exhaust gases into the crankcase.

Accumulating, cause an increase in pressure in the sump. Displace oil from crankcase. To eliminate the leak, it is necessary to restore the normal level of pressure.

3. Valve cover.

A common occurrence in engines with a range of more than one hundred thousand kilometers. To eliminate the leak, the valve cover is dismantled. The gasket is washed and smeared with sealant. Get back in place.

4. Distributor.

Oil leakage from under the distributor is not such a rare occurrence. It is often observed in domestic cars. To eliminate the malfunction, the cover is removed from the distributor.

The distributor is dismantled. The junction is neatly and abundantly smeared with sealant. You can return the distributor to its original place.

5. Oil filter.

When an oil change is garage conditions without a special tool, the oil filter is not clamped correctly. They squeeze or they don't squeeze. There is an oil leak through the filter element. Just tighten or replace the filter.

6. Pallet damage.

Careless off-road driving without special training is fraught with damage to the crankcase. Violation of the integrity of the pan leads to oil leakage. Dismantling and repair of the pallet will be performed. Installing a crankcase guard will reduce the risk of damage.

7. Crankshaft seals.

The engine uses front and rear oil seals. crankshaft. As wear increases, oil begins to leak. After parking the car, small oil spots appear on the asphalt.

Determine the location of the oil leak. You will have to dismantle the motor for a quality seal replacement. The process is time-consuming and requires the use of special equipment. It is not possible to replace the seal on your own. You will have to seek help from specialists.

How to find the location of an engine oil leak?

The causes of the leak cannot be determined without searching weak spot in the motor. A difficult task, as it seems at first glance. It takes a lot of time and requires patience.

The search for a leak is hampered by the impossibility of inspecting the engine from all sides. You have to be smart to identify problem areas.

Ways to find an oil leak:

probe

Used to control the oil level. Marks on the surface show the minimum, average and maximum oil level in the crankcase.

The level check is performed on a cooled motor. The probe is removed from mounting hole. The surface is cleaned of oil. It returns to its original position with subsequent healing outward to clarify the level.

If the level is low add oil. After 30 minutes, a control check is made. A drop in the oil level for a short time indicates damage to the crankcase. The crankcase needs to be repaired, as the operation of the machine is impossible.

Fluorescent check

An article about oil leaks from a car engine - causes, consequences, ways to fix the problem. At the end of the article - a video on how to determine where the oil is flowing from.

Varieties of leakage

If the leaks you find under the bottom of the car look greasy and dirty brown or yellow, then it's probably an oil leak from the engine. And with a pinkish or reddish tint to the flowing liquid, we can conclude that this is antifreeze leaving the automatic transmission.

Consequences of an oil leak

Oil lubrication for a car is like blood for a biological organism, because it is the lubrication that ensures the engine's performance. Based on this fact, in no case should you turn a blind eye to an oil leak, otherwise it will lead to engine blockages, failure and even fire.

Another dangerous consequence of oil leakage lies in the possible damage to the motor due to lack or lack of lubrication during operation. In addition, for the same reason, the clutch may slip.

Solving such problems on your own is often either difficult or impossible at all, and then it will be more reliable to contact a car service.

How to find a leak

A visual sign warning of leakage should be considered the appearance of a bluish haze from under the hood, as well as jerks on the oil indicator when the car is moving.

But in order to specifically identify the leakage of oil, you first need to check its level. Do this with a special probe. It must be removed, wiped dry with a clean rag to such an extent that you can see the mark. After that, dip to the end and then remove.

This way you can determine the level of lubrication. And, if it turns out to be less than normal, then oil should be added. And after adding, start monitoring its level every thirty minutes. If it falls very rapidly, it means that the oil pan is damaged.

The next way to find a leak is - use of fluorescent dye and ultraviolet light. To this end, dissolve the dye in the oil and pour the resulting mixture into the motor. Next, start the car. Wait for the motor to run for Idling ten minutes, then turn off the engine and illuminate with ultraviolet light.

You will find an oil leak in the place that will be highlighted the brightest. If the oil line is damaged, when the engine is started, oil will begin to flow due to high pressure. Under this circumstance, the oil line must be replaced.

Another way - application of talc. Sprinkle potential leaks with as much talcum powder as possible. After that, start the engine and fix idling on it for 10-15 minutes.

The meaning of this technique lies in the fact that during the operation of the motor, the points of oil leakage will appear exactly where it is sprinkled with talcum powder. This is a fairly convenient and cheap method for detecting oil leaks. It is very important to find an oil leak in time and quickly fix this problem.

Causes of leakage and ways to solve the problem

It must be remembered that the problem is not where the oil goes, but where it comes from. In most cases, the grease leaves in the following places:

• stuffing box;
• oil filter;
• distributor;
• valve cover;
• laying of the pallet crankcase;
• belt or chain pulley;
• crankshaft seals.

The earlier the year of manufacture of the motor, the greater the likelihood of a problem from aging of the seal or gasket. If used for a long time, these parts may lose their flexibility or be physically damaged. Of course, then they will have to be replaced.

It is much more unpleasant if the worn-out shaft became the cause of the oil level drop through the stuffing box. The fact is that sometimes, from regular friction against the stuffing box, a chip occurs on the shaft, through which the oil flows.

To eliminate this malfunction, it is necessary to replace the shaft, and this is a very expensive "pleasure". And the dismantling of the shaft itself is a rather laborious process, because you have to disassemble the entire engine.

The front seal wears out much faster than the rear. If you have to replace the crankshaft oil seals, then it will be useful to immediately change the camshaft oil seals.

Next possible reason leaks - poor crankcase ventilation. The fact is that gases accumulate in the crankcase, due to which pressure arises. And the purpose of ventilation is to lower this pressure.

When the ventilation passages are clogged, the pressure in the crankcase begins to force the oil out, and as a result, a leak forms. Therefore, before eliminating any leakage, it is worth debugging proper ventilation.

Another reason for the leak excessive wear piston group motor. With such a malfunction, a leak is inevitable even with perfect crankcase ventilation. It simply cannot handle the large amount of gases entering the crankcase, and the result is high pressure. With this reason, there is only one way out - replacing the piston.

If you notice oil streams coming from under the oil filter, this problem can be fixed by yourself. To do this, just tighten the filter harder, and the oil will stop running.

If you find that grease is running out of the sump, remove the sump and inspect it. If the pallet is deformed, it is worth straightening, and then putting the pallet in place, sealing the connection points with sealant.

Leaks from the valve cover are eliminated as follows: the gasket must be removed, washed, and then, covered with sealant, put in place.

In addition, oil may begin to leak at the distributor fixing points. In order to solve this problem, you will have to unscrew the mounting bolts, dismantle the distributor, then cover the junction with sealant and, at the end of the procedure, put the distributor in its rightful place.

In conclusion, we say that in most cases the problem of oil loss in the engine can be solved independently. Of course, there are many such situations when it becomes necessary to send the car to a service station - and this must be done.
And most importantly, before each trip, inspect the car very carefully. This simple procedure will save you both time and money.

An engine oil leak should not be ignored. Oil leaks can leave greasy, ugly stains on the road. But the real danger lies in the potential for engine damage, particularly when running with insufficient lubrication. An oil leak can also cause clutch slippage if your vehicle is operated with a manual transmission. The oil may also produce blue smoke and unpleasant odors if it drips onto a hot exhaust manifold or exhaust pipe.

The first sign of a problem is usually drops or smudges under your car after it has been parked overnight. If the color of the fluid is dark brown or yellow, and it looks slippery and greasy, then it is most likely engine oil. The pink or red color of the slippery liquid most likely means it comes from automatic transmission, while a green or orange liquid with a sweet smell is most likely antifreeze. The clear oily fluid is likely to be power steering fluid.

To find an oil leak from the engine, we can t need:

1. Rags or paper towels
2. Fluorescent dye
3. UV or blue light
4. Talc powder
5. Steam cleaner
6. Cellophane
7. Insulating tape or tape
8. Compressed air (compressor or pumping mechanisms).

1. First, check the engine oil level. Open the hood of your car and remove the dipstick. Wipe all the oil off the dipstick with a rag or paper towel to see the mark that indicates the correct oil level. Lower the dipstick back into the hole and then pull it back out. See how much less oil there is than expected, according to the marks on the dipstick. Add oil if the level is low. Continue checking every 30 minutes. Rapid oil leakage may indicate possibly damaged oil pan.

2. Use a fluorescent leak detection system. A combination of ultraviolet or blue light and a fluorescent dye can find small oil leaks. Add the dye directly to the engine along with the oil (but be sure to read the instructions on the dye package first) and let your engine idle for 5-10 minutes. Then turn off the engine and shine a fluorescent light over the engine. Brightly glowing areas will show oil leaks.

3. Apply a thin layer of talc around the engine. Start the car for about 15 minutes. If an oil leak appears on the surface of the engine, it will appear on the powder, which will allow you to clearly locate the leak.

4. Test the oil line. Start the car. If it is the oil lines that are the source of the leak, oil will squirt out when it is pressurized due to the engine running. Oil lines in this case should be replaced (or at worst repaired with silicone tape).

5. After you find an oil leak, make sure that this is the only leak. If oil is leaking in more than one place, then this may be due to too high pressure in the engine lubrication system. Since the pressure in the crankcase can have several causes, including its violation of its geometric integrity (dent), it is highly advisable for you to go to a specialized car service to diagnose the problem.

6. Pre-cleaning the engine with steam before looking for an oil leak makes it much easier to find a leak at the expense of the engine. Glue plastic bags around connectors, sensors, and wire bundles and secure with tape. Coat the contaminated surface of the motor with a special degreasing spray and leave for the time indicated in the instructions. By using a steam cleaner, you will be able to remove any grease or hardened dirt in this way.

• Fluorescent leak detection systems as well as engine cleaning and degreasing sprays are available at most auto parts stores.
• The best time to check the engine oil level is after your engine has been running for 10 minutes.
• Fluorescent dyes should remain in your vehicle's lubrication system after an oil leak is detected so that you can recheck the problem after a repair.
• Steam pressure washers can be rented from some home improvement stores.
• Use a degreaser that is safe for plastic and silicone.

Where do engine oil leaks most often occur?

Engine oil leaks occur most often at the valve cover or oil pan gaskets, at the belt or chain pulley, and at the front and rear crankshaft seals. In older engines, prolonged exposure to heat causes gaskets to harden and crack. Heat can also cause rubber (neoprene) gaskets and seals to lose elasticity. Moreover, the older the engine, the more likely it is that an oil leak will appear due to the aging of gaskets and seals.

An oil leak can also occur if the crankcase is overfilled with oil or due to clogging of the positive crankcase breather, allowing pressure to build up inside the engine.

Meanwhile, when oil leaks out of the engine, it attracts dirt... a lot of dirt onto itself. So look for greasy dirt around the engine and below the gaskets, seams and seals. Sometimes you may even see oil dripping while the engine is idling. But more often than not, the oil just seeps slowly, causing grease to build up in the immediate vicinity of the leak.

Over time, drivers develop a useful habit - before getting into a car, they inspect the roadbed under the wheels of their car. Are there any fresh stains from operating fluids. Dark oil slicks are causing some motorists to worry and head straight to the station Maintenance. Meanwhile, in some cases, you can fix the oil leak yourself. Consider causes and remedies for engine oil leakage.

Quite often, engine oil leaks due to poor crankcase ventilation. As you know, part of the exhaust gases breaks into the crankcase through piston rings especially if the engine is worn out. The gases accumulating in the crankcase create excess pressure, and the crankcase ventilation system is used precisely to reduce this pressure. If the channels of the ventilation system are contaminated, the resulting excess pressure can "squeeze" the oil out of the engine. That is why before eliminating any oil leaks from the engine, it is necessary to restore the normal operation of the crankcase ventilation system.

If the engine, or rather its piston system, is badly worn out, then even with a normally working crankcase ventilation, oil leakage cannot be avoided. The ventilation will not cope with a large amount of gases breaking through into the crankcase, and excess pressure will still arise there.

If oil leaks appear from under the valve cover, then it must be removed, washed, greased with sealant on all sides and reinstalled.

If an oil leak is found in the place where is the distributor attached, you need to remove the cover from the distributor, while noticing the location of the slider. After that, remove the distributor by unscrewing the mounting bolts. Lubricate the joint with sealant and install the distributor in place so that the slider is in the same position as before dismantling.

Oil drips from under the oil filter not very dangerous. Try tightening the filter, and if that doesn't help, replace it.

Oil leaks from the crankcase of the engine and gearbox are eliminated by removing the pallet, straightening (if the pallet is deformed from impact) and installing it in place using a sealant. Moreover, if a gasket was previously used, then it is easier to throw it away - the sealant will completely replace it.

By the way, installing crankcase protection will solve many problems, including preventing oil leakage due to breakdown and deformation of the crankcase.

Oil leak repair from under the crankshaft seals- a rather laborious procedure. To do this, you will need to replace the seals, and to do this, you will have to disassemble the engine. Usually the front seal wears out faster than the rear. New oil seals must also be installed using sealant, lubricating the shaft and the working surface of the oil seal with it.

You should not delay the replacement of worn oil seals, and if you had to change the crankshaft oil seals, it is best to also replace the camshaft oil seal so as not to disassemble the engine once again.

All other detected oil leaks are eliminated in similar ways, that is, by tightening the fasteners and sealing the joints by replacing gaskets and applying sealant.