Cause of oil leaks on the engine. Oil flows from under the oil filter: why is this happening and what should the driver do

Experienced drivers, after driving the car out of the garage, look to see if there are any stains or smudges left on the floor under the car. Seeing oil drops on the floor, many novice motorists immediately rush to give the car for repair to a car service, while not understanding the reasons for the oil leak and estimating the approximate cost of repairs.

There are several reasons for oil leakage, let's consider them in detail:

1. Poor crankcase ventilation. Wear of the piston group.

It happens that part of the exhaust gases enters the crankcase, bypassing the piston rings. This usually happens when the engine is worn out and needs to be repaired. The gases accumulated in the crankcase create excess pressure, thereby squeezing out the oil.

2. Oil leak in the oil sensor area.

The oil sensor gasket wears out over time and oil begins to leak at the junction.

3. Oil leak in the oil filter area.

If there is a leak in the area oil filter It usually doesn't pose much of a threat. You just need to tighten the oil filter or change it if necessary.

4. Seal leakage.

Over time, the oil seals on the car become coarse and cannot cope with their task. Sometimes it also happens that the oil seal breaks and therefore oil starts to run out from under it. The seals themselves are inexpensive, which cannot be said about replacing them.

5. Leakage from under the gasket of the engine or gearbox pan.

Also a fairly common cause of oil leakage. It is solved by replacing the gaskets with new ones or by using automotive sealant.

It is worth remembering that oil- This is one of the main fluids in the car, which ensures its performance. Therefore, if you find an oil leak, then you should not postpone repairs until later. If your knowledge and skills are sufficient to carry out repairs to eliminate an oil leak, then you can act on your own. But what if you do not shine with knowledge in the field of car mechanics? Then it is better to entrust the repair to professionals in a specialized

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

Consequences of an oil leak

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

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 engine to idle for about 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 possible locations talc leaks as profusely 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

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

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 of the piston group of the motor. With such a malfunction, a leak is inevitable even with perfect crankcase ventilation. It simply cannot cope with the large amount of gases entering the crankcase, and as a result, there 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.

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 diagnostics. power unit.

In this article, we will talk about why it occurs, and how to eliminate oil leakage from under the 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 cover protects the entire 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 influence 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;
• oil filter clogging;
• jamming of the 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. He is losing his throughput 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.

This problem is eliminated 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 is better to give preference here to the original spare part, having learned 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 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. Eliminating the causes high blood 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.

Any oil leaks in the car can indicate quite serious problems. So it will be much better and easier to perform high-quality diagnostics immediately after you notice drops of oil in the garage on the floor or in a long parking lot. If an oil stain forms under the car, then the situation requires an immediate response. There are the most serious risks of losing expensive units due to their complete wear. Running with insufficient lubrication or no lubricating fluid at all can completely destroy many parts of your car. It is worth remembering this so as not to become a victim of a very simple breakdown, which in the future can lead to very backfire. It is difficult to imagine a transport that would never in its life require attention on this occasion.

You can sometimes notice oil smudges in the engine compartment directly on the units. The technical fluids in the car are quite viscous, so when they hit the surface once, they spread perfectly over all the details and are very for a long time are not washed off even with special means. Therefore, on the engine and gearbox housings, you can quite simply notice oil streaks, which immediately turn black and collect dust. This is the main aspect of engine pollution. If any gasket or oil filler cap is loose, lubricant will spill during operation. All this makes it quite easy to perform a full inspection, even without specialists, to find out the basic possible problems. Let's look at the possible dripping of grease under the car.

Engine - problems with oil and its leakage

There are literally dozens of options for the leakage of technical fluid from the crankcase. The first thing to check is the drain screw in the crankcase of your power unit. This item has quite high quality in fact in all cars and lasts a very long time. But many screws have rubber seals that fail over time. So it will not be superfluous to check this out. Also, the causes of oil leakage may be the following:

• when topping up or when replacing the lubricating technical fluid, a little oil was spilled, due to which the lubricant flowed down the engine for quite a long time and dripped down;
• drops can form when checking the lubrication level in the engine - a not too viscous liquid from the dipstick may well fall to the floor, and then there will be a feeling of a breakdown in the car;
• crankcase damage is another problem that often leads to significant leaks of technical fluid under the car, it is not always possible to determine visually;
• a crack in the engine block leads to the fact that during operation, the oil is literally squeezed out of the once sealed chambers, so that the entire unit is dirty;
• there are other problems that require instant solutions, an oil filter with a poor design may leak or Low quality, it's hard to check.

During engine operation, the oil pressure in the system is quite high. So in case of any malfunction, the lubricant will find its way out and drip. If it digs even without pressure, on a standing car in the garage, then you should pay special attention to possible problems. After a certain time, you can simply be left without an engine. And in such a situation, you need to watch the oil level in the crankcase of the power unit as often as possible.

Gearbox is another source of dripping oil

It is possible that the drops of oil you see under the car caused the dripping from the gearbox. There is also a drain hole for lubricating fluid which should be checked first. But sometimes it drips in the most unexpected places. This is especially true for domestic gearboxes, the reliability of which is very doubtful. You can identify such a range of problems if you see drops of oil under the box:

• the bolt acting as a drain plug is damaged, the oil seal of this bolt has deteriorated, which led to the active expulsion of oil from the unit up to the last drops;
• the cover flew off, through which oil is poured into the gearbox, and under pressure, all the oil was expelled from the box, which is very dirty, and grease residues are actively dripping from it;
• the anthers of the inner CV joint, which is included in the gearbox, are damaged, through which grease can actively drip in unlimited quantities onto the floor of your garage;
• the body of the box was damaged by hitting a bump on the road, which led to a crack in the unit itself and the oil being driven out through a certain hole formed at the same time;
• it is possible to drive oil through broken axle shafts that are bent or out of their usual installation location, in which case the oil exit path from the gearbox opens.

It is almost impossible to check all these situations at home. But you can easily conduct qualitative research at the service station. To do this, you just need to give the task to the masters to see where the oil is dripping from. If you are sure that the problem is in the gearbox, it is worth immediately diagnosing this unit, checking the fluid level and performing other maintenance tasks. Often this will help stop smudges.

Is it leaking oil from under your car?

If you regularly find drops or even puddles of a viscous oily liquid under the car, you need to first make sure that the problem is really with the oil. Perhaps this is just the water that has accumulated during the trip, which washes away long-term pollution and drains when the car is in a calm position. There are other options for the formation of unpleasant puddles during the operation and storage of the car. It is worth doing the following checks:

• take a piece of white paper cotton swab draw liquid from a puddle and anoint the paper, look at the result and wait a few seconds to be sure;
• if you have oil in front of you, the paper will become more transparent in the place where you smeared it with liquid, you will also see a greasy stain that does not go away for a long period of time;
• if the stain is just wet, then you are dealing with a different liquid, it can be just water from the washer reservoir or rainwater collected in certain grooves;
• in case the paper began to turn green, red or blue, it is worth checking the cooling system, most likely, the leak comes from there, and there is antifreeze on the garage floor;
• with a constant frequency of the appearance of liquid on the floor in the place where the car is stored, it is still necessary to carry out a full-fledged high-quality diagnostics and solve all problems.

Do not use the barbaric methods of verification, which are so much written about on the Internet today. Spare your car and take it to the master. You can simply show the car to an experienced person who knows more than you in technical aspects and can really help you complete all tasks efficiently and in a short time. All this will really help to troubleshoot and fix it in order to get rid of unpleasant and alarming smudges.

Diagnostics at the service station - what to pay special attention to?

It also happens that after many months of fighting leaks, the owner of the car goes to the service station. Here he is given an unrealistic bill for replacing some oil seal, he goes home happy, and the next morning he notices familiar stains on the garage floor that have not gone away. Inspection at the station is best done together with the master, so as not to miss anything important. It is also worth giving certain conditions to a specialist:

• fully tell where the liquid oozes from, how it looks, how much it flows out - give all the information that you only have in your arsenal on the problem;
• then ask you to carefully examine all the details that we talked about above, while many craftsmen can persuade you, even without inspection, to simply change any detail;
• order diagnostics of the unit from which the liquid flows, this will help to understand the causes of such an unpleasant effect, as well as eliminate the consequences of the leak as a whole;
• order a full service for this unit, so that the master tops up the oil if necessary or changes it altogether, and also checks the levels of all technical fluids in your car;
• in addition to these solutions, it is also worth checking the integrity of all anthers, which will help prevent leakage of grease mixed with water (very similar to oil).

With such a set of interesting features, you can simply get to the point and fix the problem. Most likely, during the diagnostic process, a node will be found that needs to be serviced with high quality. You will be able to get maximum confidence with all the above processes without any problems. But for this you need to choose a professional station. Do not trust the inspection and repair of the car to unverified specialists - this can have a very bad effect on the health of the transport. The problem can also be in banal things, such as in the following video:

Summing up

You can talk for a long time about how exactly the diagnosis and repair of the car is carried out. But it's better not to wait a second if you really notice dangerous symptoms with your transport. The best solution in this case would be to perform a quality inspection on your own right at the place where you first noticed an unpleasant moment. If you do not find a leak, you should immediately go to the experts. In the absence of confidence in the safety of a particular problem, it is better for you to seek the help of specialists as quickly as possible.

Also, do not experiment in this situation. It is necessary to determine exactly where the oil is oozing from in order to simply remove it. It is also worth warning about possible problems of the main units. To do this, you need to check the oil level in them constantly, use a variety of tools to get information about what exactly is wrong in your car. This will help to correct the situation and repair the problem without much difficulty. But it’s not worth driving a car for a long time, from under which oil flows. It is better to immediately go to the service station. Have you ever had a situation when technical fluids flowed from under the car?

Experienced drivers, after driving the car out of the garage, look to see if there are any stains or smudges left on the floor under the car. Seeing oil drops on the floor, many novice motorists immediately rush to give the car for repair to a car service, while not understanding the reasons for the oil leak and estimating the approximate cost of repairs.

There are several reasons for oil leakage, let's consider them in detail:

1. Poor crankcase ventilation. Wear of the piston group.

It happens that part of the exhaust gases enters the crankcase, bypassing the piston rings. This usually happens when the engine is worn out and needs to be repaired. The gases accumulated in the crankcase create excess pressure, thereby squeezing out the oil.

2. Oil leak in the oil sensor area.

The oil sensor gasket wears out over time and oil begins to leak at the junction.

3. Oil leak in the oil filter area.

If there is a leak in the oil filter area, then this usually does not pose a big threat. You just need to tighten the oil filter or change it if necessary.

4. Seal leakage.

Over time, the oil seals on the car become coarse and cannot cope with their task. Sometimes it also happens that the oil seal breaks and therefore oil starts to run out from under it. The seals themselves are inexpensive, which cannot be said about replacing them.

5. Leakage from under the gasket of the engine or gearbox pan.

Also a fairly common cause of oil leakage. It is solved by replacing the gaskets with new ones or by using automotive sealant.

It is worth remembering that oil- This is one of the main fluids in the car, which ensures its performance. Therefore, if you find an oil leak, then you should not postpone repairs until later. If your knowledge and skills are sufficient to carry out repairs to eliminate an oil leak, then you can act on your own. But what if you do not shine with knowledge in the field of car mechanics? Then it is better to entrust the repair to professionals in a specialized