Mazda 6 cars for the Russian market are equipped with transversely arranged four-stroke gasoline engines with an inline vertical cylinder arrangement of 1.8 liters (120 hp), 2.0 liters (147 hp) and 2.5 liters (170 hp) of liquid cooling

 Конструкция и возможные неисправности двигателя автомобиля Мазда 6Конструкция и возможные неисправности двигателя автомобиля Мазда 6

Engines with an upper arrangement of two five support camshafts have four valves for each cylinder

The camshafts of the engines are driven by a plate chain, the tension of which is provided by an automatic tensioner

On all motors, the valves are driven directly from the camshafts through cylindrical pushrods, which simultaneously serve as adjusting elements of the gaps in the valve actuator.

The cylinder head is made of aluminum alloy according to the transverse cylinder purge scheme (inlet and outlet channels are located on opposite sides of the head). The valve seats and guide bushings are pressed into the head

 Конструкция и возможные неисправности двигателя автомобиля Мазда 6

The intake and exhaust valves are equipped with one spring each, fixed through a plate with two breadcrumbs. The block head is centered on the block by two bushings and is attached to the block by ten bolts

A non-shrinking metal-reinforced gasket is installed between the block and the head. In the upper part of the cylinder head there are five bearings of sliding bearings of two camshafts

The lower parts of the supports are made in one piece with the cylinder head, and the upper (covers) are bolted to the head.

The holes of the supports are processed assembled with lids, so the lids are not interchangeable, each of them has an ordinal number

On 2.0 and 2.5 l engines with variable valve timing phases, the function of the front supports is performed by the caliper of the dynamic valve timing adjustment system, which simultaneously keeps the camshafts from axial displacement.

The cylinder block is a single casting made of special high-strength cast iron, forming cylinders, a cooling jacket, the upper part of the crankcase and five crankshaft supports made in the form of crankcase partitions

The cylinders are drilled directly into the body of the block. In the lower part of the block there are five beds of main bearings with removable covers bolted to the block.

The caps of the main bearings are processed in assembly with the block and are not interchangeable

In the bearing beds (in the upper parts of the supports) there are outlet openings of oil channels designed to lubricate the main bearings, and through holes into which ball valves with nozzles are pressed, through which oil is sprayed onto the bottoms of pistons and cylinder walls.

The cylinder block has special tides, flanges and holes for fixing parts, assemblies and aggregates, as well as channels of the main oil line.

The crankshaft, made of high-strength cast iron, rotates in the main bearings, equipped with thin-walled steel inserts with an anti-friction layer

The upper liners installed in the cylinder block have a groove on the inner surface and a through slot through which oil flows from the outlet of the oil channel to the ball valve with a nozzle

There are no grooves or slots in the lower inserts. The axial movement of the crankshaft is limited by two identical thrust half-rings made in one piece with the insert of the middle main bearing.

A flywheel is attached to the rear end of the crankshaft with six bolts. At the front end of the crankshaft, a gas distribution mechanism drive sprocket and a drive pulley for auxiliary units are installed.

 Конструкция и возможные неисправности двигателя автомобиля Мазда 6

The 2.5 l engine is equipped with balancing shafts 6 (fig.) made of cast iron. The shafts are mounted in the housing 7, fixed in the lower part of the cylinder block.

The balancing shafts are connected to each other by bevel gears and are driven by a crankshaft gear mounted in place of the counterweight.

Balancing shafts are used to reduce the inertial forces of vertical vibrations caused by the movement of parts of the crank mechanism.

Pistons with a short skirt are made of aluminum alloy

Конструкция и возможные неисправности двигателя автомобиля Мазда 6

Annular grooves are made on the cylindrical surface of the piston head for the oil removal and two compression rings

Six drilling holes in the groove of the oil ring are designed to drain the oil removed by the ring from the cylinder walls. Through two of these drills, oil is supplied to the piston pin.

Piston pins of tubular cross-section are installed in the bosses of pistons with a gap and pressed with tension into the upper heads of connecting rods, which with their lower heads are connected to the connecting rod necks of the crankshaft through thin-walled inserts, the design of which is similar to the root inserts

Конструкция и возможные неисправности двигателя автомобиля Мазда 6

Connecting rods are steel, forged, with an I-beam rod. Connecting rods are processed assembled with covers. In order not to confuse them during assembly, the serial number of the cylinder is applied to the side surfaces of the connecting rods and covers.

Camshafts are cast, cast iron.

 Конструкция и возможные неисправности двигателя автомобиля Мазда 6

Gas distribution mechanism (fig.) closed with a plastic cylinder head cover. An oil separator of the crankcase ventilation system is installed in it.

Combined lubrication system

Конструкция и возможные неисправности двигателя автомобиля Мазда 6

The oil sump, cast from an aluminum alloy, is attached from below to the cylinder block. The flange of the oil sump is sealed with a sealant gasket. There is an oil drain hole in the crankcase, closed with a threaded plug.

The oil filter is full-flow, non-removable (as an option, a collapsible oil filter with a replaceable filter element made of porous paper can be installed), with bypass and anti-drainage valves.

The crankcase ventilation system is closed, forced, with the discharge of crankcase gases through the oil separator into the air filter cavity.

The engine cooling system is sealed, with an expansion tank

The engine power system consists of an electric fuel pump installed in the fuel tank, a throttle assembly, a fuel fine filter and a fuel pressure regulator installed in the fuel pump module, a fuel pressure pulsation compensator, injectors and fuel pipelines, and also includes an air filter.

The exhaust gas recirculation system with a recirculation valve driven by a stepper motor, according to the signals of the electronic unit of the engine control system, passes part of the exhaust gases into the intake pipeline.

This reduces the toxicity of car emissions and compliance with modern environmental standards.

The ignition system is microprocessor-based, consists of individual ignition coils and spark plugs.

The ignition coils are controlled by an electronic engine control system unit. The ignition system does not require maintenance and adjustment during operation.

The engine control system includes an electronic control unit (controller), temperature and absolute pressure sensors in the intake pipe, throttle position, coolant temperature, crankshaft position, camshaft position, outdoor air temperature, oxygen concentration (control and diagnostic), accelerator pedal position, brake and clutch, detonation, as well as actuators, connectors and fuses.

The power unit (engine with gearbox, clutch and main gear) is mounted on three supports with elastic rubber elements: two front ones that perceive the bulk of the power unit. and the rear, compensating for the torque from the transmission and the loads that occur when the car starts moving, acceleration and braking.

The system of changing the valve timing of 2.0 and 2.5 l engines. This system allows you to set the optimal phases

gas distribution for each moment of engine operation, which, in turn, achieves increased power, better fuel efficiency and less exhaust gas toxicity.

 Конструкция и возможные неисправности двигателя автомобиля Мазда 6

The valve timing mechanism mounted on the intake camshaft, at the signal of the electronic engine control unit, turns the shaft to the required angle in accordance with the engine operating mode.

The valve timing mechanism is a hydraulic mechanism connected to the engine lubrication system. Oil from the engine lubrication system flows through the channels to the gas distribution mechanism

Конструкция и возможные неисправности двигателя автомобиля Мазда 6

The rotor 2 turns the camshaft at the command of the engine control unit.

To determine the instantaneous position of the camshaft, a camshaft position sensor is installed at the rear of the camshaft.

A position sensor control ring is located on the camshaft neck.

A VCT caliper 5 is installed on the front of the cylinder head, which simultaneously performs the functions of the front bearing covers and the holder oil seals of camshafts.

An electromagnetic valve, a hydraulic control mechanism, is fixed on the cylinder head. The electromagnetic valve, in turn, is controlled by an electronic engine control unit.

 Конструкция и возможные неисправности двигателя автомобиля Мазда 6

The use of the VCT mechanism ensures a smooth change in the angle of installation of the intake camshaft to the positions of early and late opening of the valve timing

The control unit determines the position of the intake camshaft based on the signals of the phase sensor and the crankshaft position sensor and issues a command to change the position of the shaft

In accordance with this command, the spool of the solenoid valve moves, for example, in the direction of greater advance of the opening of the intake valves

At the same time, the oil supplied under pressure enters through a channel in the housing of the gas distribution mechanism into the housing of the VCT mechanism and causes the camshaft to rotate in the desired direction.

When the spool is moved in the direction corresponding to the earlier opening of the valves, the channel for their later opening is automatically connected to the drain channel.

 Конструкция и возможные неисправности двигателя автомобиля Мазда 6

If the camshaft has turned to the required angle, the solenoid valve spool is set to the position at the command of the control unit, at which the oil is maintained under pressure on both sides of each of the rotor blades of the coupling

If it is necessary to turn the camshaft towards a later opening of the valves, the control process is carried out with the oil supply in the opposite direction.

The elements of the VCT system (electromagnetic valves and mechanisms for dynamically changing the position of camshafts) are precision-made components

In this regard, when performing maintenance or repair of the gas distribution phase change system, only replacement of the assembled system elements is allowed.

 Конструкция и возможные неисправности двигателя автомобиля Мазда 6

The intake manifold is plastic, with variable geometry and additional 3 vortex flaps at the entrance to each cylinder.

When the engine is running with a low load, the vortex dampers are closed and create a vortex motion of the fuel-air mixture entering the cylinder, which contributes to a more complete combustion of fuel

This reduces fuel consumption and exhaust gas toxicity.

When the load increases, the vortex dampers open under the action of a vacuum supplied to the valve actuator 1 through an electromagnetic valve controlled by the electronic engine unit

Конструкция и возможные неисправности двигателя автомобиля Мазда 6

An electromagnetic valve for controlling the length of the intake manifold channels is installed next to the vortex damper control valve on the cylinder head.

Through this valve, the vacuum is supplied to the drive of 2 dampers that change the length of the intake manifold channels depending on the engine crankshaft speed. When the engine is not running, the flaps 1 are open

When starting the engine, the dampers are closed under the action of vacuum and remain closed until the engine crankshaft speed exceeds 4500 min-1 - the length of the intake manifold channels is minimal

If the rotational speed becomes higher than the specified value, the dampers open at the command of the electronic engine control unit, as a result of which an additional volume is connected to the intake manifold channels.

Controlling the length of the intake manifold channels makes it possible to improve the filling of the cylinders with air by using resonant boost, as a result of which the engine"s power and fuel efficiency indicators are improved

Possible engine malfunctions, their causes and methods of correction

The engine does not start

- no fuel pressure in the ramp:

Fuel lines are clogged - flush and purge the fuel tank and fuel lines;

The fuel filter is clogged - replace it;

The fuel pump is faulty - replace it;

The fuel pressure regulator is faulty - replace it;

The ignition system is faulty - see the engine management system;

The crankshaft position sensor is faulty - replace it.

The engine runs erratically or stalls at idle:

Insufficient pressure in the fuel ramp - see the malfunction "The engine does not start";

The throttle position sensor is faulty or the throttle assembly is dirty - replace the throttle assembly or flush the throttle valve;

Suction of air through the crankcase ventilation hoses and the hose connecting the intake manifold to the vacuum brake booster - tighten the fastening clamps, replace the damaged hoses

The valve timing system is faulty - it is necessary to diagnose and repair the system

The engine does not develop full power and is not sufficiently pick-up:

Incomplete throttle opening - flush the throttle valve or replace the throttle assembly

The throttle position sensor is faulty - replace the throttle assembly

Insufficient fuel pressure in the fuel ramp - see the malfunction "The engine does not start"

The air filter is dirty - replace the filter element How to replace the air filter element of a Mazda 6 car

The ignition system is faulty - see "Engine management system"

Gaps in the valve actuator mechanism are broken - adjust the gaps How to adjust the valve gaps of the Mazda 6 engine

Insufficient compression (below 1 MPa (10 kgf/cm2)):

- the cylinder head gasket is punctured - replace the gasket;

- burnout of pistons, breakage or occurrence of piston rings - clean the rings and grooves of pistons from carbon deposits, replace the damaged rings and piston;

- poor fit of the valves to the seats - replace the damaged valves, sand the seats;

- excessive wear of cylinders and piston rings - replace pistons, waste and repair cylinders;

The valve timing system is faulty - it is necessary to diagnose and repair the system

Insufficient oil pressure in a warmed-up engine

- the use of oil of an inappropriate brand

Replace the oil with the recommended one

- dilution or foaming of oil due to penetration of fuel or coolant into the oil sump

Eliminate the causes of fuel or coolant penetration. Replace the oil

- contamination of the working cavity or wear of the oil pump

Flush or repair the oil pump

- clogging of the oil filter

Replace the oil filter

- loosening of the attachment or clogging of the oil receiver

Fix the oil receiver, rinse its filter

- increased clearance between the inserts of the main or connecting rod bearings and the crankshaft necks

Sand the necks and replace the liners

- cracks, pores in the walls of the oil channels of the cylinder block or clogging of oil lines

Repair the cylinder block. If it is impossible to eliminate the defect, replace the unit

- loose installation of oil channel plugs or their absence

Restore the tightness of the plugs, install the missing plugs

Increased oil consumption

- oil leakage through the engine seals

Tighten the fasteners or replace the gaskets and oil seals

- the crankcase ventilation system is clogged

Flush the Crankcase ventilation System Parts How to Clean the crankcase ventilation system of the Mazda 6 engine

- wear of piston rings or engine cylinders

Waste the cylinders and replace the pistons and rings

- piston rings breakage

Replace the rings

- coking of oil-removing rings or grooves in piston grooves

Clean the rings and grooves from carbon deposits, replace the engine oil

- wear or damage to the oil-removing valve caps

Replace the oil caps Replacing the oil caps of the Mazda 6 engine

- increased wear of valve rods or guide bushings

Replace the valves, repair the cylinder head

Knocking of the main bearings of the crankshaft

Usually the knock is a dull tone, metallic.

A knock is detected when the throttle valves are opened sharply at idle. Its frequency increases with an increase in the speed of rotation of the crankshaft.

Excessive axial clearance of the crankshaft causes a sharper knock, with uneven intervals, especially noticeable with a smooth increase or decrease in the speed of the crankshaft

- insufficient oil pressure

See the malfunction "Insufficient oil pressure on a warmed-up engine"

- the flywheel mounting bolts are loosened

Tighten the bolts with the recommended torque Removing and installing the Mazda 6 engine flywheel

- increased clearance between the necks and liners of the main bearings

Sand the necks and replace the liners

- increased clearance in the thrust bearing of the crankshaft

Replace the thrust half rings, check the gap

Knocking of connecting rod bearings

Usually, the knock of connecting rod bearings is sharper than the knock of the root bearings. It is listened to when the engine is idling when the throttle is abruptly opened. The place of knocking is easy to determine by turning off the spark plugs in turn

- insufficient oil pressure

See the malfunction "Insufficient oil pressure on a warmed-up engine"

- excessive clearance between the piston rings and the grooves on the piston

Replace rings or pistons with rings

Increased noise of the gas distribution mechanism

- increased gaps in the valve drive mechanism

Adjust the Valve Drive Clearances How to Adjust the Valve Clearances of the Mazda 6 Engine - valve spring failure

Replace the spring

- excessive clearance between the valve stem and the guide sleeve

Replace the valve and guide sleeve

- wear of camshafts

Replace the camshafts

Knocking on a cold engine is audible for 2-3 minutes after starting and intensifying with an increase in the speed of the crankshaft

- increased clearance between pistons and cylinders

The sound of the pistons disappearing after the engine warms up is not a sign of a malfunction. With constant knocking, replace the pistons, waste and hone the cylinders

- loosening of the crankshaft pulley attachment

Tighten the mount

Short-term knocks immediately after starting the engine

- the use of oil of an inappropriate brand

Replace the oil

- increased axial clearance of the crankshaft

Replace the thrust half rings of the middle main bearing

- increased clearance in the front root bearing

Replace the front main bearing liners

Knocks in the warmed-up engine in idle mode

- loosening of tension or wear of the drive belt of auxiliary units

Replace the belt

- increased gaps between piston pins and holes in piston bosses

Replace pistons and fingers

- noise of gas distribution mechanism parts

We are looking at the malfunction "Increased noise of the gas distribution mechanism"

- use of substandard oil

Replace the oil

- increased clearance between crankshaft crank necks and liners

Replace the liners and sand the necks

- - the axes of the upper and lower connecting rod heads are not parallel

Replace the connecting rod

Strong knocks in a warmed-up engine when the crankshaft speed increases

- breakdown of the crankshaft pulley hub

Replace damaged parts

- cracks or breaks on the belt of auxiliary units

Replace the damaged belt

- loosened flywheel attachment Removal and installation of the Mazda 6 engine flywheel

Tighten the flywheel mounting bolts

- excessive increase in the gaps between the inserts of connecting rod and main bearings of the crankshaft

Re-sand the necks to the repair size and replace the liners

Increased vibration of the engine

- crankshaft imbalance

Remove and rebalance the crankshaft

- pistons of different weights are installed

Disassemble the connecting rod-piston group, pick up the pistons by weight

- unequal gaps in the valve drive mechanism

Adjust the gaps

- unequal compression values in the cylinders

Check compression and replace faulty parts

- the cushions of the suspension supports of the power unit are heavily worn or hardened How to replace the supports of the power plant of the Mazda 6 car

Replace the supports

- loosened fastening of the crankshaft pulley or pulleys of auxiliary units

Tighten the mount

Engine overheating

- insufficient amount of liquid in the cooling system

Add coolant to the cooling system

- the outer surface of the radiator is heavily soiled

Clean the outer surface of the radiator with a jet of water

- the thermostat is faulty

Replace the thermostat

- the electric fan of the cooling system is faulty

Check the fan motor, replace the faulty parts

- the valve of the expansion tank plug is faulty (it is constantly open, which is why the system is under atmospheric pressure)

Replace the expansion tank plug

- use of gasoline with a reduced octane number

Fill in the conditioned gasoline

- the cylinder head gasket is damaged

Replace the gasket

With a certain skill and care, many malfunctions of the engine and its systems can be fairly accurately determined by the color of the smoke coming out of the exhaust pipe. Blue smoke indicates the ingress of oil into the combustion chambers, and constant smoking is a sign of severe wear of the parts of the cylinder piston group. The appearance of smoke during overheating, after prolonged scrolling by the starter, after long idling or immediately after braking by the engine indicates, as a rule, the wear of the oil-removing valve caps. Black smoke is a sign of too rich a mixture due to a malfunction of the engine control system or injectors. Bluish or thick white smoke with an admixture of moisture (especially after the engine overheats) means that the coolant has entered the combustion chamber through a damaged cylinder head gasket. With severe damage to this gasket, the liquid sometimes gets into the oil sump, the oil level rises sharply, and the oil itself turns into a cloudy whitish emulsion. White smoke (steam) with an unheated engine in wet or cold weather is a normal phenomenon.

Quite often you can see a car standing in the middle of a city traffic jam with an open hood emitting clouds of steam. Overheating. It is better, of course, not to allow this, looking at the temperature indicator more often. But no one is immune from the fact that the thermostat, the electric fan may suddenly fail or the coolant will simply flow. If you missed the moment of overheating, do not panic and do not aggravate the situation. Overheating is not as terrible as its possible consequences. Never immediately turn off the engine: it will get a heat stroke and, possibly, after cooling down, it will refuse to start at all. After stopping, let it run at idle, while the fluid circulation will remain in the system. Turn on the heater at maximum power and open the hood. If possible, water the radiator with cold water. Only after achieving a decrease in temperature, stop the engine. But never immediately open the plug of the expansion tank - on an overheated engine, a geyser from under the open plug is provided to you. Take your time, let everything cool down, so you will save the health of the car and your own health.

Almost all instructions for the car contain a recommendation to squeeze the clutch when starting the engine. This recommendation is justified only in case of start-up in severe frost, so as not to waste battery energy on turning the shafts and gears of the gearbox in thickened oil. In other cases, this measure is aimed only at ensuring that the car does not move if the transmission is switched on due to forgetfulness. This technique is harmful to the engine, since when the clutch is squeezed out, a significant force is transmitted through it to the thrust bearing of the crankshaft, and when starting (especially cold), the lubricant does not come to it for a long time. The bearing wears out quickly, the crankshaft gets an axial backlash, starting from a place begins to be accompanied by a strong vibration. In order not to spoil the engine, make it a habit to check the position of the gear lever before starting and start the engine with the parking brake tightened, without squeezing the clutch unless absolutely necessary