Peugeot/Citroen 2.2 HDI engine (DW12)

Diesel engine with index DW12 is a modification of the DW10 power unit with a capacity of 2 liters. To achieve more power and volume up to 2.2 liters allowed to increase the stroke of pistons, as well as the introduction of a cylinder head with 16 valves. The power unit includes a variable-length manifold, a turbine modern at the time of production, and balancing shafts. The designers managed to achieve an increase in engine output and higher environmental performance.

The first DW12 power unit was produced in 2000. The motor with a volume of 2.2 liters and power of 136 horsepower was installed on cars of French production, Peugeot 406, Citroen C5. There were also produced modifications of engines with a capacity of 101 horsepower. Such motors were equipped with commercial vehicles of the same manufacturers.

The first version of the power unit was replaced by a biturbo engine with the same volume. The engine developed a power of 170 horsepower, was equipped with two turbines and became the first diesel four of French production. Later the concern produced similar units with capacity from 150 to 204 horsepower. Installation of such motors was relevant for French manufacturers, as well as for such brands of passenger cars as Ford, Mitsubishi, Land Rover.

Reliability and durability are the main advantages of 2.2 HDI motors. At the same time, minor breakdowns and defects can occur quite often. With competent and timely maintenance, a mileage of 500 thousand kilometers and more is not considered something special. But even such reliable motors have weak points, which are a source of expensive repairs.

Technical characteristics

Motor and Vacuum System Wiring Failures

One of the shortcomings of the 2.2 HDI motor is the unfortunate wiring layout under the hood of the car. Electrical cables are collected in harnesses and corrugations. In the process of operation, the wiring is often fixed by fraying and breaks. Accordingly, the engine may stop at the most inopportune moment. The service center has to check the integrity and condition of hoses, electro-vacuum valves, other mechanisms.

Breakdowns can be fixed on the valves themselves, despite the reliable design. Most often defects occur in the vacuum system. For the power unit, this means a drop in power, dynamics, traction. Such defects are fixed in any mode of operation of the power unit.

Owners of machinery with DW12 motors turn to the service when the mud filter or flow meter is clogged. Specialists determine the jamming of the turbine geometry, incorrect operation of the EGR valve. There can be a failure of the intercooler pipes due to cracks.

Why the powertrain will not start

Problems with the priming pump are the main reasons why the 2.2 HDI motor does not start. Masters of service centers check first of all this very node. If the problem is in the operability of the pump, the repair will cost inexpensive. With other breakdowns, the cost of eliminating defects is significantly higher.

Faults of the air distributor

The presence of an air distributor in the intake tract of the power unit 2.2 HDI is a feature of such motors. The available two air swap channels work independently of each other. In normal operation mode of the engine the upper channel is used. If it is necessary to activate the mode of particulate filter burning or supply of heated air stream, the second channel is used. Independent dampers are provided to control these lines.

Standard problems of damper drives are wear of working gears, breakage of rods and axles. The main reasons for such defects are the use of plastic in production, which is subject to rapid wear. Any such situation leads to poor performance of the power unit. Motor performance and traction are reduced. If you remove the particulate filter and block it at the program level, the need to use the flaps disappears.

Another defect is oil leakage at the commutation points of the metering unit and spigots. Grease gets on the starter, which can lead to failure of the unit. Therefore, special attention should be paid to the condition of the spigots.

Faults of heat exchangers

DW12 power units are equipped with two heat exchangers. The first of them cools the exhaust gases with antifreeze. The second circuit is responsible for heating the air flow entering the motor without feeding the intercooler. This circuit is engaged in the mode of burning the particulate filter.

The main problem of heat exchangers is the leakage of circuits. Such defects are recorded quite rarely. It is possible to understand the need for repair by thick exhaust. Such symptoms are observed at any mode of operation of the power unit.

Disadvantages of the damper pulley

The crankshaft pulley of the damper type is installed on all modifications of the 2.2 HDI engine. At high mileage and with intensive use of the vehicle, wear of the rubber cage of the pulley is observed. The inner and outer parts of the mechanism slip, the driver notices extraneous knocks and squeaks when the motor is running. The only option to solve the problem is to replace the pulley with a similar part.

Another problem of the motor is oil leaking into the intake channel. Most often such a defect is observed when the breather pipe is damaged. For DW12 diesel engines, oil consumption at the level of 1 liter per 100 thousand kilometers of mileage is not a defect. If the lubricant is consumed faster, it is necessary to contact a service center.

Turbine and intake manifold problems

The DW12 powertrain includes an intake manifold with channels of vortex and direct types. Flaps are used to cut off the straight lines. Motors labeled 4HH are characterized by closed flaps by default. For 4HW power units, the intake passages are closed when the engine shaft speed is reduced.

To control the flaps, each motor includes a servo actuator with an integral diaphragm. It is not uncommon for the rubber element to be torn or damaged. In such situations, problems in the performance of the vacuum system are recorded. The geometry change actuator begins to function in the maximum boost mode. Due to the lack of rarefaction, the turbine overblows, on the diagnosis this is indicated by the corresponding error code.

Another problem of the engine is considered a breakage of the plastic stem. In some cases, the loss of the ball and the flap axis is recorded. Overlapping of the air supply to the power unit occurs according to a random algorithm. For the car, this means a loss of power and traction. If you shut off the flaps on the intake manifold, such problems can often be minimized. In this case, the powertrain works in the same mode, without any complaints.

The main breakdowns of the turbine

Developers of DW12 powertrain used a turbine of Garrett brand, modification GT1549P. The peculiarity of the mechanism was the original system of changing the geometry. Turbine blades are placed around the impeller, and the angle of attack does not change in different modes of operation. The blades are fixed on the ash pan, which is responsible for movement along the impeller.

By increasing the amount of vane retraction in the heated part of the compressor, the gases are forced more actively onto the impeller. When the gas level is sufficient, the pressure is relieved. For this purpose, the actuator moves the blades with the ash pan in the opposite direction.

Of the main turbine faults for the DW12 engine, stem wedging can be noted. As a result, the turbine boost is above or below the desired level. Another problem is the gradual wear of the bearings and shaft. In such cases, oil consumption increases, up to 0.5 liters per every 1,000 kilometers. If this indicator increases even more, the power unit can fail within a few minutes after starting and working in any mode. The presence of whistling signals the turbine’s imminent failure.

EGR valve problems

For power units 2.2 HDI is characterized by the possibility of rapid diagnosis of the state of the EGR valve. Masters of service centers distinguish typical problems of these units. Most often wedging of the mechanism is fixed. As a result, the gas supply mode is disturbed, the power unit loses power. The driver diagnoses uneven acceleration of the car, which may not respond to the gas pedal or move in the normal mode. The simplest and most effective option is to shut off the EGR valve, while re-flashing the module is not required.

Special features of injector replacement

DW12 motors are characterized by difficulties in removing the injectors. Such problems are caused by the presence of moisture in the wells, accumulating over time. As a result, the injectors stick and unscrew very hard. Citroen and Peugeot vehicles are characterized by the absence of a cover on the power unit. If the drainage channels are clogged, moisture condenses and gets on the injectors.

It is best to use a hydraulic tool to dismantle the injectors. If the pressure exceeds 12 tons and the nozzle does not budge, it is likely to collapse. An excellent option for motors of this brand is the installation of a homemade or purchased cover. Such a simple measure prevents moisture from getting on the injectors, respectively, their replacement does not require much effort. The spark plugs on DW12 motors are also unscrewed with difficulty, because they are located in hard-to-reach places.

Transmission timing malfunctions

The 2.2 HDI power units with an output of 136 horsepower or less are equipped with a timing belt, from which the torque is transmitted to the fuel injector. A special device is used for replacement and subsequent tension adjustment. The frequency of tension is measured between the pulleys of the exhaust camshaft and the fuel injector.

In normal operation mode, the timing belt withstands 160 thousand kilometers of mileage. If the car is used intensively and with heavy loads, it is necessary to change the node every 120 thousand kilometers. When replacing, masters of service centers sometimes diagnose oil leakage. The weakest places of the motor are the oil seals of the camshaft and crankshaft.

Motor breakdowns caused by crankshaft sprocket rotation

The presence of moisture on the timing belt is also common on 2.2 HDI engines. Moisture flows to the gears, gets under the drive casing in the area of the support. For some vehicle models, water freezing on the pulley or belt teeth is relevant. When starting a cold engine, the belt may slip. Despite the elaborate design of the motor, in which the valves and pistons do not collide, the problem lies in weak rockers. These nodes simply fail. Restore the performance of the engine can only be restored by replacing them.

Another problem caused by freezing moisture on the belt is the degradation of the bolt and key of the belt pulley. There are also cases of the camshaft sprocket rotating. If the mileage of the vehicle exceeds 250 thousand, the sprockets can slip for no apparent reason. Especially often such situations occur when starting the engine in severe frost, driving on a flexible hitch, trying to start the engine “from the pushchart”.

Rassynchronization of the star and camshaft can be of different degrees. Depending on the severity of the breakage, the power unit can stop starting, or will work intermittently. In the first case, the diagnosis of the motor reveals an error with the code P0340. The consequence of such a breakdown is the collision of pistons and valves, failure of rockers.

The rotation of the star relative to the camshaft entails the corresponding repair. But even if you return the elements to their original place, there is no guarantee that the sprockets will not rotate again. It is desirable to replace the camshaft with a similar unit.

Problems in the operation of the camshaft chain

Power units 2.2 HDI, manufactured in the period from 2001 to 2002, have in the composition of the chain of low strength. This node transmits torque to the intake camshaft, the width of the outer and inner plates is 10 and 8 mm, respectively. In subsequent modifications of the motor, these indicators increased to 12 and 10 mm.

The first chains rarely worked more than 200 thousand kilometers, after which they could break. After modification, the chains began to go 400 thousand kilometers without any failures. The main problems are related to the stretching of the links. If the driver notices extraneous noises and rustling, failures in the operation of the power unit, the chain must be replaced.

Problems in the operation of the fuel injector

The composition of this type of motor includes a fuel pump manufactured by Bosch. The equipment is characterized by reliability, repair of the node is required very rarely. The main problems are associated with the wear of plunger pairs, which, if necessary, can be promptly changed.

For this brand of fuel injectors are characterized by leaks of sealing rubbers and gaskets located under the cover. Such problems occur in severe frosts or when the engine is warmed up to a high temperature. It is best to change the entire set of seals. Consumables are sold as a single repair kit. In some cases, the presence of leaks leads to a failure to start the engine.

Special features of Bosch injectors

Another reliable and durable node of power units are injectors of the Bosch brand. If there are problems, their cause can be identified at a modern diagnostic center. The main defects of these units are damage or wear of sealing washers, burnout of rings. As a result, compression decreases, injector wells are covered with soot and carbon deposits.

It is possible to recognize the need for diagnostics of injectors by poor quality start of the power unit. Most often such problems occur when starting a hot engine. Fuel overflow or weak pressure rise leads to similar consequences. Due to the affordable price and ease of replacement, repair of injectors is inexpensive. Another cause of breakdowns can be leaks at the return channel connections. Replacing the seals can eliminate the problem.

Reduction valve malfunctions

There is another typical problem with 2.2 HDI engines. Owners are faced with situations in which the engine starts intermittently or without any problems with a certain periodicity. Often the power unit begins to stall at increased rpm or at idle. When driving, the engine rpm may “float”, thrust is lost and reappears. Most likely, repair or replacement of the pressure regulator, which is part of the fuel injector, is required. If replacement is not possible, you can simply clean the unit.

The pressure regulator includes a metal filter element that screens out debris and chips. It is inadmissible to remove the mesh, as all the debris will get inside the system. Cleaning the filter helps in most cases. If the clogging is fixed frequently, the problem is in the fuel system.