Possible causes of engine oil leakage

The engine eats oil: what are the reasons and what to do?

The main signs by which you can determine that the engine is eating oil:

• The oil level on the dipstick “drops” quickly;

• Exhaust gases are blue;

• Oiling and coking of spark plug electrodes;

• Traces of oil in the throttle valve assembly and in the turbine area;

• Oil leakage through the crankshaft oil seals;

• Oil in the expansion tank.

Why does the engine eat up oil?

There may be several reasons why engine oil disappears. This is oil waste due to a faulty CPG (cylinder-piston group), worn valve guides and valve stem seals, as well as a faulty crankcase ventilation system.

Worn valve bushings

Increased oil consumption also occurs in cases where the turbine shaft bushings are worn out, low-grade motor oil is filled in, when a crack appears in the cylinder block or cylinder head, oil leaks from under the filter or valve covers, as well as through the crankshaft seals.

You can see how oil is leaking from under the oil filter. Oil is leaking from under the valve cover

And the last thing that directly depends on the car owner is operating the power unit to the limit with an aggressive driving style.

Let's look at the reasons point by point

• Oil waste – bluish color of the exhaust

The piston rings are worn out or coked, which does not allow them to remove excess oil from the cylinder surface and when it enters the combustion chamber it burns along with the fuel.

This piston has coked rings and cracked partitions. Engine 1.4 TSI

This happens due to the use of low grade oil, which contaminates the piston grooves and rings with decay products (carbon deposits), which lose the ability to “play” in the cylinder, repeating its profile, this is especially important when repositioning the piston when it passes the bottom dead center.

The oil scraper rings are the first to lose mobility, ceasing to remove excess oil from the cylinder mirror, which, when burned, “flies out” of the muffler in the form of bluish smoke.

The partitions on the pistons themselves may be cracked, as well as the grooves for the rings are worn out and the rings, when moving to top dead center, produce a pumping action, lifting the oil into the combustion chamber, where it also burns.

Alternatively, the rings may not be installed correctly when the engine is assembled and they are not doing their job. This especially applies to the oil scraper ring and the second compression ring, which has a protrusion in the form of a scraper, with which it also partially helps the oil scraper remove excess oil from the cylinder mirror.

A similar thing happens when cylinder liners wear out, when an ellipse-shaped wear appears in them, which leads to a decrease in compression and increased oil consumption.

If the valve stem seals are worn out, blue exhaust smoke will be observed when the engine warms up, and traces of oil will appear on the threads of the spark plugs. Or the exhaust is clean, but if you press the accelerator pedal sharply, a bluish smoke appears.

Worn valve stem seals

If the crankcase ventilation does not work properly, then the gases are poorly cleared of oil particles, which are drawn into the starting manifold, then into the cylinders and burn.

When oil burns out, its level in the engine sump also decreases, which reduces its ability to cool and causes it to heat up even more. If you skip this moment and do not take any measures, the engine will face complex and expensive repairs or replacement.

• Oil leak – there is no oil in the exhaust gases:

– wear of the turbine rotor support bushings due to insufficient oil pressure in the line, which leads to oil leakage, as well as a malfunction of the oil seal, when oil will fly into the exhaust pipe, appearing at the outlet in the form of strong smoke when the pipe is heated, and sometimes even drain from pipes in the form of drops. This situation is extremely dangerous, since the turbine is capable of “sucking” all the oil from the engine sump;

There are scuffs on the journals and bushings of the support bearings. Turbocharging

– cracks in the jacket of the cylinder block or cylinder head, oil getting into the cooling system;

crack in cylinder head

– low-grade oil, which leads to intense wear of the rubbing pairs, overheating of the engine, and as a result, rapid failure of all seals, which simply “dumb”, which leads to oil leakage through the seals and gaskets;

– pressure sensor squeezed out and oil leaking.

Oil leak from pressure sensor

How to eliminate high oil consumption?

A medium repair or major overhaul of the engine will help, depending on the degree of wear of the CPG, crankshaft liners, and the condition of the cylinder head, which is determined when disassembling the power unit.

Replace valve seals.

This operation will give a positive result if the valve guides are not worn, otherwise the replacement will only have a short-term effect and the seals will again begin to leak oil into the combustion chamber. This is due to the fact that the valve will not operate in the center of the bushing, but will deviate towards the wear of the bushing, while pressing on the edge of the oil seal, which will quickly disable it.

The way out of the situation is to replace the bushings, for which you will have to dismantle the cylinder head for repairs.

Drain the low-grade oil, flush the engine, fill with oil that meets the viscosity and quality requirements of the manufacturer. The lower the viscosity of the oil, the thinner it is and the more capable it is of leaking through oil seals and other engine seals. The issue of oil quality in this case is only trust in the retail outlet or car service where it is replaced.

Replace faulty seals and gaskets.

The photo shows oil leaking from under the valve cover. Here it is enough to replace the gasket.

Restore or replace the oil pump to create the required pressure in the line.

Avoid aggression when driving a car, which will extend its service life and eliminate the problem of high oil consumption.

Monitor the level and always use the oil prescribed by the manufacturer, without skimping on low-grade analogues.

Source: https://avtoexperts.ru/article/pochemu-dvigatel-est-maslo-chto-delat-i-kakie-prichiny/

Maslozhor. Oil consumption on 1.8 and 2.0 TFSI engines

Why does a not-yet-old engine from a renowned company suddenly begin to consume oil? Is this a system or an accident? Alexander Shabanov and Mikhail Kolodochkin are investigating the problem with the participation of Alexander Mikhailovich Pakhomov.

The increased oil consumption of some modern engines, or “ oil burner ,” as it is often called, is one of the most discussed topics on Internet forums. And this is not idle chatter.

For example, on some Volkswagen TFSI engines (EA888) produced in 2009-2012, the most common types (1.8T and 2.

0T) with a mileage of 60 thousand to 120 thousand kilometers, oil consumption for waste begins to increase sharply - up to a liter and a half per thousand kilometers.

We will tell you about the 1.8T turbo engine, which had very indecent consumption: 400 ml of oil per 100 km. Not a thousand kilometers, but a hundred! And this is not an isolated case.

The autopsy showed

The engine malfunction revealed two critical, in our opinion, circumstances.

First : the oil scraper ring is completely clogged with black deposits of unknown nature. The same deposits were observed on the second sealing ring. They were present both on the outer side of the ring, adjacent to the cylinder, and on the inner side, where the expander spring is located.

Its coils were practically caked due to this dirt, and therefore the expander was inoperative. It's funny that the coils of the expander spring are imprinted on the cast iron of the ring body. This usually does not happen because the spring moves relative to the piston groove. These prints clearly indicate that the ring is motionless.

Which means it doesn't work.

Second : the spring of the oil scraper ring expander, which should ensure its pressing against the cylinder walls, has noticeably lost its elasticity. This happens when it overheats.

This part is heat-fixed, that is, it receives its elasticity in the process of appropriate heat treatment.

Its overheating above the thermosetting temperature leads to the so-called release of the spring, that is, to a loss of elasticity.

Let's discuss further. In a working engine, when the piston moves up and down, the rings also periodically move from the lower end of the groove to the upper. This is called ring repositioning.

The shifting moment is determined by the direction of movement of the piston and the pressure difference acting on the ring.

But if the gap in the groove itself is completely filled with oil, then when the ring is moved from the upper end to the lower end, part of the oil is pumped upward into the combustion chamber (the so-called pumping effect).

During normal operation of the rings, only traces of oil are observed in the grooves. The oil film sits on the cylinder wall - the pumping effect does not appear. But if there is no drainage, the rings begin to pump oil into the cylinder. This is exactly the case: the tiny drainage holes are clogged with dirt.

Stagnation of oil in the grooves in the absence of drainage and elevated temperatures leads to accelerated aging and decomposition of the oil - this is how the very black deposits that we observed when opening the engine are born.

Another possible reason for a sharp increase in oil loss is a non-working oil ring expander spring. This ring is the most important element of the combustion chamber sealing system of a piston engine. Its task is to regulate the distribution of oil in the area of the compression rings, which take on the main gas load.

If this regulation (i.e. oil restriction) stops working, then the thickness of the oil layer left by the first piston ring on the cylinder walls increases sharply. With it, oil consumption for waste also increases.

Error or environmental cost?

What is the reason for this oil consumption? And what is this - a design feature of the motor or an accident?

When you open such a motor, the miniature pistons immediately catch your eye ( Photo 4 ).

This is a modern trend in the design of high-speed engines: designers are trying to lighten the piston as much as possible - in order to reduce the inertial loads on the connecting rod and crankshaft, as well as to reduce the force of pressing the piston against the cylinder walls.

All this helps to reduce friction losses in the engine, leading to an increase in its mechanical and effective efficiency. The goal is to reduce fuel consumption and, most importantly, the content of carbon dioxide CO2 in the exhaust gases.

As a result, the piston turns out to be “short”. If previously it was accepted that the height of the piston should be no less than the diameter of the cylinder, now this rule has been abandoned.

Moreover, a T-shaped piston design is now used, in which the supporting part of the side surface is reduced as much as possible - only segments of the side surface of the throne (skirt) remain in a plane perpendicular to the piston pin axis. This also reduces friction losses. But the negative effects of reducing the piston size are obvious.

With increasing loads in a forced engine, a smaller amount of iron that receives them works under more severe conditions. The temperature of the piston increases, and so does the voltage in it. The consequence is a decrease in service life and reliability. And, as a special case, the possibility of overheating of the piston group.

That's not all. To reduce the temperature of the piston, it is cooled by a stream of oil from nozzles embedded in the main oil line of the engine. In the engines under consideration, these injectors have valves that open at a pressure exceeding 0.18 MPa (0.25 MPa in new versions).

This is done because when the injectors open, the oil pressure in the line drops, and this can deprive some of the bearings of lubricant. But oil pressure depends on two parameters - the engine oil temperature (the higher it is, the lower the pressure) and the crankshaft speed.

This means that in the most unfavorable operating conditions of the engine - at high ambient temperatures, low speeds and high load - the pistons are not cooled! After all, the injectors are closed at low pressure!

In short, the engine can easily be killed if you load the car to capacity on a hot summer day and drag it in high gear up a long climb.

Another feature of this Volkswagen engine is the size of the piston rings. They are unusually narrow.

In addition, the height of the first ring is only 1.0 mm, the second one is 1.2 mm, and the oil scraper ring is 1.5 mm! This seems completely strange - after all, neither in our GOST standards, nor in the German DIN, nor even in the catalogs of piston rings from leading companies, we found rings with a height of 1.0 mm with a cylinder diameter of 82.5 mm; turns out this is some kind of special order.

What does this mean? A ring with such dimensions reduces its mechanical strength. This is especially important for the oil scraper ring box. To compensate for the decrease in strength, the ring manufacturer went to reduce the already small drainage holes in it. Hence, there is an increased risk of their coking and complete loss of drainage.

Another important aspect. For normal operation, the piston ring must be pressed against the cylinder wall - otherwise there is no seal.

The ring is pressed by the pressure of gas forces, which is sufficient only during the compression and expansion strokes, that is, less than half the duration of the operating cycle. The rest of the time, the force of its own elasticity works.

But the smaller the ring size, the less pressure it can create on the cylinder wall. And this is a parameter enshrined in regulatory documents: a lot depends on it.

By the way, there is such a thing as piston ring flutter: a certain oscillatory process in which the ring operates unstably, does not seal “through the gas” and drives the oil upward. So, reduced radial pressure is one of the factors that contributes to the occurrence of this very flutter.

But that's not all. Instead of the usual first o-ring, we saw a so-called torsion bar, which has a tricky pattern on the inner surface.

Such a chamfer creates a different moment of resistance in different sections of the ring, and this leads to its “twisting”, which increases the local specific pressure on the cylinder wall.

But even in theory they don’t do that! The installation of torsion rings as the first rings was at one time considered unacceptable due to their negative impact on the wear rate of the first piston groove.

A “skewed” ring creates increased contact pressure not only on the surface of a durable steel or cast iron cylinder, but also on the groove in the piston - soft and pliable, because the piston is made of an aluminum alloy and is also very hot. We look carefully at the piston of the disassembled engine.

Yep, that’s right: to compensate for this negative, the first groove is cut into a special cast-iron wear-resistant insert ( Photo 3 ). But such an insert, while protecting against wear, interferes with the normal cooling of the piston - after all, the thermal conductivity of cast iron is five times less than that of the aluminum alloy of the piston, and such an insert interferes with the flow of heat flow. This is an additional way to overheat both the piston and the oil scraper ring.

And finally, another “discovery”. Usually, special through holes are drilled in the piston to drain oil from the oil scraper ring operating area. But even here a surprise awaited us.

Not only are the drainage holes tiny, there were only four of them ( Photo 5 )! The pistons of similar engines, as a rule, have at least eight of them ( Photo 6 ).

And once upon a time, instead of holes for drainage, slots-windows were made. Not the best solution in terms of piston strength, but the drainage always worked.

The small number of holes, coupled with their miniature size, impairs oil drainage, and this eventually leads to coking - similar to drainage in the oil scraper ring itself. We told you at the beginning of the article how the work ends in the absence of drainage.

Why was this done? Most likely, to reduce stress in the area of the groove for the oil scraper ring. It is clear that each hole is a stress concentrator, and they are already high there. By removing half of the drainage holes, we got rid of half of the concentrators - it became easier for the piston. But nothing comes for free - in the end, we got what we got.

For what?

Why did the designers create a piston group, the main solutions of which contradict the established practice of engine design? We can only assume: in order to meet the requirements of the current Euro-5 standards and the new Euro-6 standards for toxicity and CO2 content in exhaust gases. The point is to limit the content of so-called non-fuel residual carbons, which are produced by burning motor oil: reducing waste is strictly related to toxicity. This is partly why a torsion ring was taken as the first ring, which is usually used as an oil seal.

The low height of the piston rings and trunk allows for a reduction in specific fuel consumption. This is important both in itself and as a factor in limiting CO2 output. However, the service life suffers: the specific loads on the piston, rings and cylinder walls increase, and therefore the wear rate inevitably increases. But for a modern engine, resource is no longer the main thing.

So, with a high degree of probability, the cause of the defect can be considered a non-optimal design of the engine piston group, which increases the possibility of oil overheating in the area of the piston grooves and worsens the drainage of engine oil from the oil scraper ring into the engine crankcase. All this contributes to a sharp increase in oil flow into the combustion chamber.

They will object to us: they say, not all Volkswagen engines suffer from a similar feature.

Yes, to start the “oil burner” mechanism, several circumstances must coincide: the engine was once overheated, plus frequent short trips, plus the tetanus of traffic jams, and also the unstable quality of the engine oil, clogged radiator honeycombs... Therefore, the “oil burner” is not a system , but a floating defect. But this does not make it insignificant.

A sincere confession?

Are Volkswagen engineers aware of the problem? They know! The Germans even sent out several notices to their official dealers with recommendations to correct the situation. The last point in them: if, supposedly, flashing the controller and eliminating problems with crankcase ventilation does not help, replace the piston with a new, optimized one.

Its rings are more familiar: the height of the first has increased to 1.2 mm, standard for engines of this class, the height of the second has also increased to 1.2 mm, and the oil scraper ring has increased to 2.0 mm. By the way, in new (starting from 2012) engines, a second O-ring 1.5 mm high is installed in the basic version.

That is, the company, in fact, returned to the configuration that is typical for engines produced before 2000. The width of the rings has also increased. This is important because the moment of resistance of the ring, and therefore its rigidity, depends linearly on the height, while the dependence on the width is cubic.

And if in the old version of the first compression ring the measured elastic force was less than 10 N, then in the new one it returned to the usual 15 N for engines of this size. Likewise for the remaining rings. The increased height of the oil scraper ring has improved drainage. The pistons changed accordingly.

The repair also entails replacing a set of connecting rods: they are not interchangeable with the old ones - for some reason the diameter of the piston pin has been increased by 1 mm.

By the way, attempts to order old versions of miniature piston rings and pistons for them for additional research were unsuccessful: they are no longer in warehouses! New cars are equipped with optimized rings and pistons, and Volkswagens since 2012 have had virtually no oil problems . But cars produced in 2009-2012 are at risk . And no guarantee applies to them anymore.

At dealers, the cost of such a repair kit, including replacement work, exceeds 190 thousand rubles! You have to pay for strange design solutions out of your own pocket.

What if it's cheaper? There is a solution. The standard set of miniature rings is being replaced with another one - with sizes close to those that have gone into production since 2012. In this case, the serial low-removal ring with a spring expander and a box-shaped body is replaced with a so-called three-element ring, consisting of two scrapers and a spring expander.

The old pistons are used, but the grooves for the piston rings are bored to fit the new rings. The connecting rods also remain old. By the time this article was prepared, more than a dozen engines had been treated in this way at the Stagecoach service station . The result is positive: the “oil guzzling” has stopped.

Moreover, the repair is three times cheaper than that prescribed in the notice from Volkswagen.

If trouble hasn't come yet

What to do if you are at risk, but there is no trouble yet (by the way, judging by the notice, Volkswagen considers oil consumption of more than half a liter per thousand kilometers critical)?

To begin with, watch your oil consumption . If you notice its persistent growth, do not wait for the prescribed threshold. A glass (200 ml) per thousand is enough to cause concern. At this level, there is a chance for successful therapy without drastic measures such as opening the engine: you can try to wash off deposits on the piston by, for example, performing an extraordinary oil change and flushing the engine.

Do not skimp on oil , since its stability (propensity to form deposits) is very important. Therefore - only good synthetics. It is better to avoid newfangled low-sulfur oils such as LowSAPS, since improved cleaning properties are needed. The replacement interval should be halved.

And do not force the car, do not allow the engine to overheat! The main thing is don’t try to make a mini-truck out of a car, especially on a hot summer day!

The first version of this article was published in the magazine “Behind the Wheel” 07/2015 (1009) on pp. 182-185 “Guten appetite / Oil consumption” (and is also available on the website ZR.ru - link to source). The editors of the magazine “Behind the Wheel” would like to thank the service station “Stagecoach” (St. Petersburg) and personally its director Alexander Pakhomov for their assistance in preparing the material.

Source: https://dilauto.ru/faq/172

Signs of engine oil starvation: consequences, symptoms

The oil that we pour into the engine wears out on its own, even when the car sits quietly in the garage - it oxidizes.

Moreover, oil wear is inevitable during active engine operation under heavy loads.

One of the big tests for an engine can be oil starvation - we’ll find out how to avoid it, signs and consequences, and how to determine oil starvation right now.

What is engine oil starvation?

Due to insufficient lubrication, the aluminum almost melted

For obvious reasons, if there is no lubrication in the rubbing units, they instantly fail. The danger of engine oil starvation is that it can occur instantly and almost completely destroy the main components of the engine:

crankshaft,
camshaft,
gas distribution mechanism,
cylinder-piston group,
other vital and expensive components and assemblies.

Broken camshaft key (due to insufficient lubrication)

Out of the blue!

Oil starvation does not occur out of the blue , and as a rule, all the blame for a breakdown lies only with the owner of the car or the mechanics who made the repairs.

As you know, oil is in the crankcase in the quantity required for lubrication and is supplied to the system using an oil pump.

In the case when the oil cannot reach individual rubbing units, oil starvation occurs. There can be a lot of reasons for this.

How to determine oil starvation

It was immediately clear that the engine was “starved of oil”

First, let's talk about determining engine oil starvation, since the range of symptoms is quite wide - from a drop in engine power to overheating, extraneous noise and knocking.

All this indicates wear of certain components characteristic of each engine.

For example, in the most common overhead gasoline engines, accelerated wear and increased noise during operation of the gas distribution mechanism are often encountered.

Consequences

In addition, the oil scraper rings may become stuck, which will lead to even greater excess oil consumption and engine seizure. Thick blue smoke from the exhaust pipe will indicate a malfunction of the oil scraper rings and high oil consumption.

Causes of oil starvation

Engine operation in oil starvation mode is in almost all cases accompanied by increased temperature, which must be taken into account. In addition, the oil pressure in the system can be either very low (as indicated by the oil pressure warning lamp on the instrument panel) or unstable. All this can be caused by the following reasons:

Insufficient oil level in the pan. There is simply not enough lubricant to process all the sliding bearings, there is no oil film, and the parts run almost dry. That is why it is important to check the engine oil level at least once a week, and even more often during active use. In addition, it is necessary to carefully monitor oil leaks and, if necessary, take measures to eliminate leaks.
Engine oil dipstick (analog on top, original on bottom). Incorrect dipstick readings may not promptly indicate to the car owner that the lubrication level is insufficient.
Using oil of unsuitable viscosity . This is a very important point, since, for example, 5w-30 oil, when used in summer, may not provide the required viscosity, engine lubrication will be insufficient, and pressure at high temperatures may drop critically. To avoid this, you must follow the car manufacturer's recommendations when choosing motor oils.
The oil receiver screen is clogged. The oil pump is not able to overcome the resistance of a clogged mesh, so oil cannot be supplied in the required quantity and under the required pressure to all components. The same applies to clogged oil lines. The ideal way out of this situation is to disassemble and mechanically clean the channels and oil receiver; flushing agents can only make things worse.
Oil pan clogged with dirt
Irregular or untimely oil and filter changes. Each brand of oil has its own resource, which must be strictly observed. During operation, the lubricant loses most of its lubricating properties and by the end of its service life it can be almost completely oxidized and lose viscosity.
Disassembling the oil filter
Wear of oil scraper rings and increased oil consumption . Wear of valve stem seals and crankshaft seals will also lead to high oil consumption.
Poor quality engine assembly after repair . A competent motor mechanic will never use sealant where a simple gasket is enough - the fact is that excess sealant is pressed not only outward, but also into the oil channels, clogging them over time.
Failure or clogging of the lubrication system pressure reducing valve.
Oil filter clogged.

Video about engine oil starvation at high speeds

conclusions

As you can see, there can be plenty of reasons for oil starvation, and in order to prevent breakdowns, you just need to check the oil level from time to time and follow the rules for changing it, and eliminate leaks in a timely manner. Then the engine will last a long time without expensive repairs. Good quality oil to everyone and good roads!

Source: http://carfrance.ru/opredelyaem-maslyanoe-golodanie-dvigatelya-prichiny-priznaki-i-posledstviya/

The engine eats oil: causes, diagnostics, repairs, additives

Many car owners sooner or later experience a significant increase in oil consumption. They say this - the engine burns oil. The reasons for this phenomenon are various. From the article you will learn why oil consumption increases, how to establish the reasons and not bring the matter to capital (overhaul of the engine).

Where does the oil disappear in a working engine?

A car with a working engine (new or after capitalization) eats oil in small quantities - 20-40 grams per thousand kilometers.

When the car operates in difficult conditions (frequent acceleration or driving uphill, driving at an altitude of over 2 thousand meters), then engine oil consumption increases to 100-200 grams per 1000 kilometers.

If the engine consumes oil in glasses and liters, it means that something is definitely wrong with it. The main reason for oil consumption: evaporation due to high temperature.

Violation of the ignition timing or fuel injection (diesel engines), as well as changes in the composition of the air-fuel mixture lead to an increase in temperature in the combustion chambers, detonation and other negative consequences. All this affects oil consumption and can lead to the need for major repairs or capital investments.

Why does oil consumption increase?

To understand why the engine began to eat oil, you need to understand what factors lead to excess consumption of lubricant and how they affect the condition of the engine. Oil consumption increases:

Crankshaft oil seal leak

motor overheating;
use of inappropriate oil viscosity;
wear of valve stem seals and rings;
malfunction of the valve or channels of the crankcase ventilation system;
poor tightening, drying out, cracking or wear of gaskets, seals and cuffs;
breakdown or burnout of the cylinder head gasket (cylinder head).

Consequences of engine overheating

Overheating of the engine leads to damage to the oil seals and the appearance of scoring on the cylinder walls.

If the overheating was minor and short-lived (the coolant did not boil), then in most cases the motor tolerates 1-2 such overheatings without consequences.

After mild but frequent overheating, the caps compress the valve worse and some of the oil gets into the intake manifold. If the engine boils, it is necessary to drive the car away for repairs, otherwise capital damage cannot be avoided.

Using oil of inappropriate viscosity

Caps, seals and cuffs also deteriorate due to the addition of incorrectly selected additives to the oil. Why this happens, read the article “Engine oil additives.”

Engines developed in the 60-80s of the twentieth century are designed to work with viscous mineral oil, so the use of liquid synthetics will lead to leaks. In addition, an engine designed for mineral oil smokes if liquid synthetic is poured into it.

More modern engines are initially designed for synthetics, so filling with mineral oil will lead to deterioration of lubrication, the appearance of scuffing on the surface of the cylinders and rings, large amounts of oil getting into the combustion chamber and repairs after 50-100 thousand kilometers. The same thing happens if you use the appropriate type of oil, but the wrong viscosity.

Wear of valve stem seals and rings

If the caps or rings are worn/damaged, oil enters the combustion chamber. The reasons for wear of these parts are described below:

high mileage;
engine overheating;
incorrect oil type or viscosity;
incorrect selection of additives;
overspeeding;
frequent operation of the engine at maximum power;
cold start.

The repair procedure in this case will consist of replacing the valve stem seals.

Malfunction of the valve or channels of the crankcase ventilation system

Fuel combustion products break through between the piston rings and cylinder walls, increasing the pressure in the crankcase. If the PVC valve is faulty, the pressure becomes too great and pushes through the seals and seals. The leak remains even if the oil is changed.

Not everyone who owns a car understands why the health of this system affects oil consumption and does not pay attention to checking it, which must be done during each diagnosis.

As a result, the valve fails, after which the channels become clogged with deposits, but the engine does not smoke or lose power.

Poor tightening, drying out, cracking or wear of gaskets, seals and seals

The cause of leaks is a skewed oil seal.

The bolts that secure the engine attachment parts must be tightened periodically. After all, gaskets dry out or shrink over time or under the influence of high temperatures and incorrectly selected additives. The same thing happens with oil seals and cuffs. As a result, oil leaks occur.

Breakdown or burnout of the cylinder head gasket

When the engine operates at conditions close to the maximum and the temperature is exceeded, breakdown or burnout of the gasket is possible. This damage is difficult to diagnose if it only affects the oil passages of the cylinder head.

In this case, the symptoms are similar to those that appear after damage to the caps or rings - that is, the engine smokes heavily or weakly.

To avoid capital damage, it is necessary to replace a punctured or burnt gasket no later than after 10 thousand kilometers.

How to determine the cause of increased oil consumption

Determining the cause of increased oil consumption occurs in four stages:

Exhaust color determination;
Leak detection;
Checking the crankcase ventilation system;
Removing the cylinder head and checking the condition of the gasket.

Exhaust color determination

This operation must be done by two people. One press on the gas pedal or the drive/throttle handle/injection pump raises the engine speed to 2-3 thousand. The second one looks to see if the engine is smoking.

On diesel engines, when you press the gas pedal sharply, black smoke may appear, which disappears after lowering the engine speed.

Gray or bluish smoke, which intensifies as the engine speed increases, indicates that oil has entered the cylinders through caps, rings or a broken gasket, so they need to be replaced. If the exhaust is clear, the caps, rings and gasket are fine.

Finding leaks

A car with severe leaks leaves oil stains on the asphalt and requires urgent repairs. Weak leaks appear only when the engine is running under load, so they leave no traces on the ground.

There should be no traces of oil on the surface of a fully functional motor. If you find a greasy wet or damp spot, then there is a leak in that place.

To clarify, you need to start the engine and leave it idling to warm up to operating temperature, and then inspect the suspicious area again.

If it does not become wet, you need to gradually, within a minute, raise the speed to maximum and carefully observe the suspicious area. If this does not help detect the leak, you will have to drive the car 10-20 kilometers, accelerating sharply from time to time.

In this mode, the pressure in the combustion chamber is much higher than usual, therefore the amount of gases breaking into the crankcase is noticeably greater.

If after such a check the suspicious place gets more wet, the problem is a malfunction of the crankcase ventilation system and poor tightening or damage to the gasket.

Checking the crankcase ventilation system

To do this, unscrew the fastening clamps and remove the PCV valve, then blow it with lips or a compressor. If it is working properly, then the air will flow only in one direction with little effort. After this, you need to remove and blow out all the hoses, then check the pipes. One of them may be clogged with dirt or sediment.

Checking the condition of the gasket

This operation is performed after detecting bluish smoke in the exhaust. There is no damage to a serviceable gasket - burnouts, cracks, ruptures. Even if the gasket is not damaged, it must be replaced with a new one. If the gasket shows signs of damage, it is necessary to check the lower plane of the cylinder head for bending. Perhaps, as a result of overheating of the engine, she spun.

Source: http://AutoLirika.ru/soveti/pochemu-dvigatel-est-maslo.html

Published on January 10, 2018, by moly shop

Even expensive cars misfire. They, just like regular cars, can damage the clutch, seat rings and shamelessly eat oil. We encountered just such a problem: a German foreign car eats oil in large quantities while emitting bluish smoke.

Today our guest is the BMW X3 - the most everyday car, very reliable, but there is one drawback - it consumes a lot of oil: just fill it up, and after two days the yellow indicator lights up at the level.

Of course, you can “shove” this car, so to speak, fill it with oil up to the mark and sell it.
The new owner won't even know about anything. But this is not our solution, so in this article let’s look at how to eliminate these problems for this “oil-guzzler”. Opening the hood of this car, we won’t hear anything special: the usual sound of a diesel engine.

Gas test

First, let's do a gas test. If you lift the cover of the “stagval sprocket” oil will start to spit out, so it’s better not to do this. There is no gas and this is good, it means everything is in order with the engine. But there is another problem: smoke is pouring out of the exhaust pipe.

This is just not very good news - apparently, engine oil gets into the combustion chamber. But how can it show up there? The fact is that oil can get there in two ways: either through scuffs, between the piston and cylinder, or through the valve stem seals.

The problem is quite serious, so to look at it in more detail, let's move to a car service.

A little background on how this happened. This is the car of one of my good friends. And somehow he was going abroad, to Spain. The path is long, and the car services are unknown. I drove about 2000 km when suddenly the turbine shut down. So I moved on.

Honestly, it would be better if he didn't do this. But what's wrong with that? A huge amount of oil began to flow into the intake, which caused the piston rings to jam. But this is what we assume, but nevertheless a clear picture will be presented to us only after the act of “opening”.

Removing injectors

To get to the combustion chamber of a diesel engine, you will have to choose one of two paths.

The first is removing the injectors. This method is very long, complex and literally jewellery. In addition, later, they will have to be screwed back, which will also take a lot of time. The second method is to remove the glow plugs. The option is also quite labor-intensive, since you will have to remove the manifold, but anything is better than working on the injectors.

So, let's start dismantling.
Our task is simple: remove the manifold, unscrew the glow plugs, pour decoking agent into the cylinders. What do we need?

A screwdriver, a couple of wrenches and half an hour of time. First, put on gloves: take pity on your hands. First, we dismantle everything that will interfere with your work on removing the exhaust manifold: spacers, pipelines, etc. A screwdriver will help a lot.

The main thing is that it is not too powerful, otherwise it can easily bend the pedantic nuts. Never throw anything at the motor - it can cost you too much. There was carbon deposits in our intake manifold. Well, it's a lost cause. Work carefully, because if you accidentally drop a bolt into the engine compartment, it will be difficult to get it out.

You will, of course, be lucky if you are equipped with a probe with a magnet. BUT still be extremely careful. All; Once the manifold is removed, start the engine. We will have black and blue smoke.

Now do everything strictly according to the instructions. Warm up the engine to a temperature of 70 degrees and only then remove the spark plugs.

Do this very carefully, as there is a huge chance of breaking them, this is especially common in older cars where the spark plugs have not been changed for a very long time. We set the pistons to the desired level, approximately in the middle, and pour the decoking agent into the cylinders.

Now you need to hurry as the engine is cooling down. By the way, I recommend warming it up outside so as not to breathe fumes in the garage.

Usually the drug is sold together with a special syringe, with which it is very convenient to pour it into the combustion chamber in doses - this is a remedy. Do everything according to the instructions. Faster! The engine is getting cold. As soon as they dialed it, it went straight into the cylinder, immediately. And so on for each cylinder.

Next, do not forget to screw the glow plugs into place.

Looking ahead, I will say that UNDER NO EVENT do you start the engine with liquid in the cylinder, otherwise you will get a water hammer: after this, oil combustion will seem like baby talk to you than the consequences that the liquid will have in the system.

You will have to wait 12 hours. On a note. If the engine is V-shaped, then more of it will be needed to ensure normal operation of the product. If it is simple, two-row, then do as described above.

Day 2.

Be careful, the product is sprayed in a stream and may splash into the eye. Now the second person must spin the wheel. Be extremely careful as the liquid will fly out very far. The liquid itself has turned from a faint coffee color to dirty brown, and I don’t like the smell either.

But in contrast to all this nasty substance, the carbon deposits on the candles disappear and dissolve absolutely completely.
So, we have completely removed the chemicals from the cylinders, now insert the spark plugs back, install the exhaust valve and start the engine.
Attention! Don't worry if the car is difficult to start, this is normal after decarbonization.

The engine simply needs to collect all the dirt left by the drug in the system, cough it up, and then your engine will start smoothly.
After our operation, the car traveled about 2000 km and there are absolutely no complaints about oil waste. There is also no smoke, so the car is completely intact.

That's how sometimes simple manipulations and a little luck can save you money.

Source: http://www.moly-shop.ru/blog/maslozhor-dvigatelya-prichiny-ustranenie