Renault Duster vehicles are equipped with engines of two modifications: the K4M of 1.6 L and the F4R of 2.0 L.
Both engines are petrol, four-stroke, four-cylinder, in-line, sixteen-valve — with twin overhead camshafts.
The engines are mounted transversely in the engine compartment.
In design, the engines are similar. The main differences relate to component dimensions.
Firing order: 1-3-4-2, counted from the flywheel.
Fuel system — sequential multi-point fuel injection.
The engine, gearbox and clutch form a powertrain mounted on three rubber-metal mounts.
The engine fuel system consists of an electric fuel pump installed in the fuel tank, a throttle body, a fine fuel filter, a coarse fuel filter located in the fuel pump module, a fuel pressure regulator, injectors, fuel pipes, an exhaust gas recirculation system and an air filter.
The engine ignition system is microprocessor-based, consisting of ignition coils and spark plugs.
The ignition coils are controlled by the electronic control unit (controller) of the engine management system.
The ignition system requires no servicing or adjustment during operation.
On the F4R engine, a phase control scheme using a dephaser is employed. The dephaser regulates the opening timing of the engine intake valves.
The system ensures the setting of optimum valve timing for every operating point of the engine in order to increase its power and dynamic characteristics by altering the position of the intake camshaft.
The system is controlled by the engine electronic control unit (ECU).
The main elements of the phase control system are the control solenoid valve, the actuator mechanism changing the camshaft position and the camshaft position sensor.
The timing belt drives the system actuator, which transmits rotation to the intake camshaft through a hydromechanical connection.
From the main oil gallery, engine oil under pressure is fed through channels to the cylinder head seat in which the valve is installed, and then through channels in the head and in the camshaft — to the system actuator.
In the initial position and at an engine crankshaft speed below 1450 rpm, no supply voltage is applied to the solenoid valve — it is closed.
At a crankshaft speed within 1450—4300 rpm and with the accelerator pedal fully depressed, the ECU applies supply voltage to the solenoid valve — it opens.
The spool device of the valve then ensures the supply of oil under pressure into the working cavity of the actuator.
Due to the change in oil pressure and the hydromechanical action, the individual elements of the actuator move relative to each other, and the camshaft rotates through the required angle, changing the valve timing.
At a crankshaft speed above 4300 rpm, the supply to the solenoid valve is cut off.
The spool device of the solenoid valve and the elements of the system actuator are very sensitive to contamination of the engine oil.
If the phase change system fails, the intake valves open and close in maximum retard mode.
The variable valve timing system allows optimum valve timing to be set for every operating point of the engine, resulting in increased power, better fuel economy and lower exhaust gas toxicity.
To determine the instantaneous position of the camshaft, a camshaft position sensor (phase sensor) is installed.
On the camshaft journal there is the trigger ring of the position sensor.
On the upper cover of the timing drive, the solenoid valve is secured which hydraulically controls the variable valve timing mechanism.
The solenoid valve is, in turn, controlled by the engine electronic control unit.
The control unit determines the position of the intake camshaft from the signals of the phase sensor and the crankshaft position sensor and issues a command to change the shaft position.
In accordance with this command, the spool of the solenoid valve moves, for example, in the direction of greater advance of the intake valve opening.
The oil supplied under pressure then passes through a channel in the timing drive housing into the housing of the phase change mechanism and causes the camshaft to rotate in the required direction.
When the spool moves in the direction corresponding to earlier valve opening, the channel for their later opening is automatically connected to the drain channel.
If the camshaft has rotated through the required angle, the spool of the solenoid valve, on command from the control unit, is set to the position in which the oil is maintained under pressure on both sides of each of the rotor vanes of the coupling.
If the camshaft needs to be rotated towards later valve opening, the control process is carried out with oil supplied in the reverse direction.
When the engine is stopped, the intake camshaft is automatically set to the initial position in which there is no overlap of intake and exhaust valve timing.
This is done to ensure reliable starting of a cold engine.
With this phase arrangement, dilution of the fresh air-fuel charge entering the cylinder during the intake stroke by exhaust gases is excluded.
In addition to easing engine starting, this ensures smooth and uninterrupted operation during warm-up.
As the engine warms up, the valve timing changes smoothly until their overlap on the fully warmed engine, which ensures better economy.
The elements of the variable valve timing system (solenoid valve and mechanism for dynamic change of the relative position of the camshafts) are precision-made assemblies.
For this reason, when servicing or repairing the variable valve timing system, only replacement of the system elements as a complete assembly is permitted.
At the front of the engine (in the direction of vehicle travel) are located: the oil level dipstick, the fuel rail with injectors, the intake pipe, the oil filter, the heat exchanger (2.0 engine), the low oil pressure warning sensor, the knock sensor, the crankshaft position sensor (2.0 engine), the coolant pump feed pipe, the starter (1.6 engine), the alternator, the power steering pump, the air conditioning compressor.
At the rear of the engine are located: the throttle body, the air filter housing, the exhaust manifold with the control oxygen sensor, the starter (2.0 engine).
The engine cylinder block is cast from cast iron, the cylinders are bored directly in the block.
In the lower part of the cylinder block are five main bearing supports of the crankshaft with detachable caps, which are secured to the block by bolts.
The holes in the cylinder block for the bearings are machined with the caps fitted, so the caps are not interchangeable.
On the end surfaces of support No. 3 of the K4M engine and No. 2 of the F4R engine, seats are provided for thrust half-rings preventing axial displacement of the crankshaft.
To cool the pistons during engine operation, their crowns are washed from below with engine oil through special jets which are pressed into the cylinder block.
Crankshaft with five main and four big-end journals.
The main and big-end bearing shells of the crankshaft are steel, thin-walled with an antifriction coating applied to their working surfaces.
On the front end of the crankshaft are fitted: the oil pump drive sprocket, the timing pulley and the auxiliary drive pulley, which is also the torsional vibration damper of the crankshaft.
The crankshaft is sealed at the front and rear by oil seals.
The connecting rods are forged steel, of I-section, machined together with the caps.
The caps are secured to the connecting rods by bolts on the F4R engine and by bolts with nuts on the K4M engine.
By their lower (crank) ends the connecting rods are connected through bearing shells to the big-end journals of the crankshaft, and by their upper ends — through gudgeon pins to the pistons.
The gudgeon pins are steel, of tubular section.
On the 2.0 engine the pin is of the floating type — it rotates freely in the piston bosses and the upper end of the connecting rod.
Against axial displacement the pin is secured by two spring circlips located in the grooves of the piston bosses.
On the 1.6 engine the gudgeon pin is pressed into the upper end of the connecting rod and rotates freely in the piston bosses.
The pistons are made of aluminium alloy.
The piston skirt has a complex shape: in longitudinal section the skirt is barrel-shaped, and in cross-section — oval.
In the upper part of the piston three grooves for the piston rings are machined.
The two upper piston rings are compression rings, and the lower one is an oil control ring.
The cylinder head is cast from aluminium alloy, common to all four cylinders.
The cylinder head is centred on the block by two dowels and secured by ten bolts.
A non-settling metal gasket is installed between the block and the head.
On opposite sides of the cylinder head are the ports of the intake and exhaust channels.
The spark plugs are installed at the centre of each combustion chamber.
The valves are steel, arranged in two rows in the cylinder head, in a V, with two intake and two exhaust valves per cylinder.
The intake valve head is larger than the exhaust one.
The valve seats and guides are pressed into the cylinder head.
Valve stem seals are fitted over the valve guides from above.
The valve closes under the action of the spring.
By its lower end it rests on a washer, and by its upper end — on a retainer held by two keepers.
The paired keepers are externally in the form of a truncated cone and internally are provided with thrust shoulders engaging the groove on the valve stem.
Two camshafts are installed in the upper part of the cylinder head.
One camshaft operates the intake valves of the valve train, while the other operates the exhaust valves.
Each shaft features eight lobes; an adjacent pair of lobes simultaneously actuates the valves (intake or exhaust) for each cylinder.
A design feature of the camshaft is that the cam lobes are press-fitted onto a tubular shaft.
The camshaft bearing supports (six per shaft) are of a split design, located between the cylinder head and the cylinder head cover.
The camshafts are driven by a toothed belt from the crankshaft pulley.
A thrust flange is machined onto each camshaft at the toothed pulley end; this flange fits into a groove in the cylinder head, thereby preventing axial movement of the shaft.
The camshaft pulley is not secured to the shaft by an interference fit, key, or pin; instead, it is held solely by the friction forces generated between the mating faces of the pulley and the shaft when the pulley retaining nut is tightened.
The camshaft nose is sealed by an oil seal fitted over the shaft journal and pressed into a bore formed by the mating surfaces of the cylinder head and the cylinder head cover.
The valves are actuated by the camshaft lobes via valve rocker arms.
To extend the service life of the camshaft and valve rocker arms, the camshaft lobe acts on the rocker arm via a roller that rotates on the rocker arm's axis.
The valve rocker arm hydraulic pivots are installed in sockets within the cylinder head.
Oil enters the hydraulic pivot from the supply gallery in the cylinder head through an opening in the pivot body.
The hydraulic lash adjuster automatically ensures zero-clearance contact between the camshaft lobe and the rocker arm roller, compensating for wear on the lobe, rocker arm, valve stem tip, and valve seat and face.
The engine utilizes a combined lubrication system.
Pressurized oil is supplied to the crankshaft main and connecting rod bearings, the camshaft bearings, and the rocker arm hydraulic lash adjusters.
Other engine components are lubricated by splash.
Oil pressure is generated by a gear-type oil pump located in the oil sump and attached to the cylinder block.
The oil pump is driven by a chain from the crankshaft.
The pump drive sprocket is mounted on the crankshaft beneath the front cylinder block cover.
The sprocket features a cylindrical collar against which the front crankshaft oil seal operates.
The sprocket is installed on the crankshaft without an interference fit and is not secured by a key.
During engine assembly, the drive sprocket is installed on the crankshaft. The spacer is clamped between the timing drive toothed pulley and the crankshaft shoulder when the assembly of components is tightened by the accessory drive pulley mounting bolt.
Torque is transmitted from the crankshaft to the sprocket solely through friction between the mating faces of the sprocket and the crankshaft.
If the accessory drive pulley mounting bolt becomes loose, the oil pump drive sprocket may begin to slip on the crankshaft, causing engine oil pressure to drop.
The oil pickup is integrated into the oil pump housing cover.
The cover is secured to the pump housing by five screws and held in place by a spring clip.
Oil flows from the pump through a passage in the cylinder block to the oil filter.
The oil filter is a non-serviceable, full-flow type.
On the F4R engine, the oil passes through a heat exchanger attached to the cylinder block before entering the filter.
During engine operation, coolant constantly circulates through the heat exchanger core.
Shortly after engine startup, the engine oil in the heat exchanger is warmed up (because the coolant heats up faster).
When the engine operates at maximum load, the oil is cooled in the heat exchanger.
After passing through the oil filter, the oil is fed into the cylinder block's main oil gallery.
From the main gallery, oil flows through channels to the crankshaft main bearings, piston cooling jets, and subsequently to the crankshaft connecting rod bearings.
Oil is supplied from the main gallery to the cylinder head via two vertical channels in the cylinder block, reaching the outermost camshaft supports (on the side of the camshaft end plugs) and the hydraulic valve lifters.
Oil enters the camshafts through grooves and drilled passages in the outermost camshaft bearing journals, and reaches the other camshaft bearings through drilled passages in the remaining journals.
Oil drains from the cylinder head back into the oil sump via vertical channels.
The crankcase ventilation system is of the closed, forced-flow type.
Gases that have leaked from the combustion chambers past the piston rings into the crankcase travel through channels in the cylinder block and cylinder head to the cylinder head cover.
After passing through the oil separator located in the cylinder head cover, crankcase gases are cleared of oil particles and then flow through the air filter housing, throttle body, intake plenum, and intake manifold into the engine cylinders.
Possible engine malfunctions
Engine does not start
No fuel pressure in the fuel rail:
- Clogged fuel lines — flush and blow out the fuel tank and fuel lines.
- Faulty fuel pump — replace the pump (Fuel module repair).
- Clogged fuel filter — replace the filter (Auxiliary fuel filter replacement).
- Faulty fuel pressure regulator — replace the pressure regulator.
- Faulty ignition system — perform engine management system diagnostics.
Engine does not develop full power and lacks sufficient throttle response
- Faulty throttle position sensor — replace the throttle body assembly (How to remove the throttle body).
- Insufficient fuel rail pressure — see above.
- Clogged air filter — replace the filter element.
- Ignition system malfunction — diagnose the engine management system.
- Insufficient compression (below 10 kg/cm²):
- Blown cylinder head gasket — replace the gasket (Replacing the cylinder head gasket).
- Piston burnout, broken or stuck piston rings — clean carbon deposits from rings and piston grooves; replace rings.
- Poor valve-to-seat sealing — replace damaged valves; grind the seats.
- Excessive cylinder and piston ring wear — replace pistons; rebore and hone cylinders.
Engine runs roughly or stalls at idle
- Insufficient fuel rail pressure — see above.
- Air leak in the hose connecting the intake plenum to the brake booster — tighten clamps; replace damaged hose.
- Ignition system malfunction — diagnose the engine management system.
Insufficient oil pressure in a warmed-up engine
- Poor oil quality — replace the oil (Replacing oil and filter).
- Oil dilution or foaming due to fuel or coolant entering the crankcase — eliminate the cause and replace the oil.
- Contamination of the working chamber or wear of oil pump components — clean or repair the oil pump.
- Clogged oil filter — replace the oil filter.
- Loose mounting or clogging of the oil pickup — clean or repair the oil pickup.
- Excessive clearance between main and connecting rod bearing shells and crankshaft journals — regrind the journals and replace the shells.
Crankshaft main bearing knock
Usually a low-pitched, metallic knocking sound. It is detected when the accelerator pedal is pressed sharply. Its frequency increases with the crankshaft speed. Excessive crankshaft axial play causes a sharper knock with irregular intervals, particularly noticeable during a gradual increase or decrease in crankshaft speed.
- Insufficient oil pressure — refer to the "Insufficient oil pressure" fault.
- Excessive clearance between the thrust flanges of the center main bearing shells and the crankshaft — replace the thrust washers (semi-rings) and check the clearance.
Connecting rod bearing knock
Connecting rod bearing knock is sharper than main bearing knock. The knock is audible at idle and when the throttle is opened sharply. The source of the knocking sound can be easily identified by disconnecting the spark plugs one by one.
- Excessive clearance between crankshaft connecting rod journals and bearings — replace the bearings and regrind the crankshaft journals.
Piston knock
A dull, muffled knocking sound caused by the piston slapping against the cylinder wall. It is most audible at low engine speeds and under load.
- Excessive clearance between pistons and cylinders — replace the pistons; bore and hone the cylinders.
- Excessive clearance between piston rings and piston ring grooves — replace the rings or the piston-and-ring assemblies.
Excessive valve train noise
- Low oil pressure in the lubrication system — see the "Insufficient oil pressure" fault.
- Camshaft lobe wear — replace the camshaft.
Knocking in a cold engine
- Audible for two to three minutes after startup and intensifying as engine speed increases:
- Excessive clearance between pistons and cylinders. Piston knock that disappears after the engine warms up is not a sign of a malfunction. If the knocking persists, replace the pistons and rebore and hone the cylinders.
- Loose crankshaft pulley mounting — tighten the pulley mounting bolt.
Brief knocking immediately after engine start-up
- Use of substandard, low-viscosity oil — replace the oil.
- Excessive crankshaft end play — replace the thrust washers.
- Excessive clearance in the front main bearing — replace the front main bearing shells.
Knocking in a warmed-up engine at idle
- Loose tension or wear of the drive belt auxiliary units — replace the belt.
Valve train noise
See "Excessive valve train noise."
- Use of substandard oil — replace the oil.
- Excessive clearance between piston pins and piston boss bores — replace pistons and pins.
- Non-parallel axes of the connecting rod's small and big ends — replace the connecting rod.
Loud knocking in a warmed-up engine at high crankshaft speeds
- Over-tensioned accessory drive belt, or cracks/tears in the belt — replace the damaged belt (Checking and replacing the accessory drive belt).
- Loose flywheel mounting — tighten the flywheel mounting bolts to the specified torque.
Excessive engine vibration
- Crankshaft imbalance — remove and balance the crankshaft.
- Uneven cylinder compression — rectify the cause of low compression.
- Severely worn powertrain mounts — replace the powertrain mounts.
Engine knocking (detonation) under load
- Use of low-octane gasoline — replace the fuel.
Excessive oil consumption
- Oil leakage through engine seals — tighten fasteners or replace gaskets.
- Clogged crankcase ventilation system — clean the crankcase ventilation system components.
- Engine piston ring wear — replace the pistons and rings.
- Broken piston rings — replace the rings.
- Coking of oil control rings or piston ring grooves due to the use of substandard oil — replace the engine oil and clean carbon deposits from the rings and grooves.
- Worn or damaged valve stem seals — replace the valve stem seals (Replacing valve stem seals).
- Excessive wear on valve stems or guides — replace the valves and repair the cylinder head.
Engine overheating
- Insufficient coolant level — top up the coolant.
- Radiator exterior heavily soiled — clean the radiator exterior with a water jet.
- Faulty thermostat — replace the thermostat (Removing the thermostat and housing).
- Faulty cooling fan — check the fan motor, activation sensor, and relay; replace any faulty components.
- Faulty expansion tank cap valve — replace the expansion tank cap.
- Use of low-octane gasoline — replace the fuel.
Rapid drop in expansion tank fluid level
- Damaged radiator — repair or replace the radiator.
- Damaged hoses or connection gaskets — replace the damaged hoses and gaskets.
- Fluid leakage through hairline cracks in the cylinder block or cylinder head — check the cylinder block and cylinder head for leaks.
