Since the early eighties Mazda started producing their own diesel engines. The 2-liter RF engine has been produced since 1984, and in more than 20 years of production it has received a huge number of changes. But something remained unchanged: for example, the geometry of the cylinder piston group.
The four-valve version appeared in 1998. It is noteworthy that the manufacturer throughout this time produced the cylinder head with a single camshaft, driving all the valves.
Two-liter Mazda engine has survived all stages of the diesel injection revolution: from the engine with pre-chamber injection to the engine with Common Rail.
Technical specifications
| Characteristics | Value |
|---|---|
| Exact volume | 1998 cm³ |
| Power system | Common Rail |
| Engine power | 110 – 145 hp |
| Torque | 310 – 360 Nm |
| Cylinder block | Cast iron, R4 |
| Cylinder head | Aluminum, 16 valves |
| Cylinder diameter | 86 mm |
| Piston stroke | 86 mm |
| Compression ratio | 16.7 |
| Engine Features | SOHC |
| Hydrocompensators | No |
| Transmission timing | Belt drive |
| Fasoregulator | No |
| Turbocharger | IHI VJ36 |
| Recommended oil | 5W-30, 4.8 liters |
| Fuel type | Diesel |
| Environmental class | Euro 4 |
| Example service life | 280,000 km |
| Engine weight | 197 kg (with attachments) |
Special features of particulate filter
Mazda 2.0 MZR-CD engine received particulate filters only after 2004. These filters are very sensitive to the quality of the fuel used: in the presence of high sulfur content, they clog very quickly. After the particulate filter gets clogged, the electronics starts to start the procedure of its burning, because of which a large volume of diesel fuel ends up in the engine oil. Because of this, Japanese specialists have added an emergency oil level mark on the oil dipstick, above the Max mark. Thanks to this, car drivers can recognize that there is not oil in the crankcase, but a formed mixture with diesel fuel.
Which oils are suitable for the engine 2.0 MZR-CD
The Mazda diesel power unit uses exclusively branded recommended oil Dexelia 5W-30 (specification ACEA C1).
Is the mass fuel consumption sensor reliable?
This sensor in the Mazda 2.0 MZR-CD engine is unreliable and fails quickly. When it is defective or dirty, the engine incorrectly determines the necessary dose of injected fuel, which causes sluggish responses to the gas, and the engine is difficult to start in freezing weather.
You can get rid of the symptoms by restarting the engine or removing the chips from the flow meter.
The features of the vacuum pump
It is installed on the rear of the motor. The vacuum pump is connected to the camshaft through a gear and spacer mounted on it. It is lubricated with oil.
The pump is unreliable, over time it begins to work, emitting a firing noise constantly or at a certain speed range of the power unit. The reason is the backlash of the bearing of its shaft, which is enough to replace. But there are also known cases when the vacuum pump jamming led to shearing of the key on the gear, which is located on the camshaft.
The pinion in this powertrain is used to drive the vacuum pump. Another of its functions is to transmit data for the camshaft position sensor. If the pinion is cut, the sensor does not receive the correct information about the camshaft position. As a result, the engine cannot be started normally.
Details about vacuum line solenoid valves
Pre-restyled RFC5 power units received seven solenoid valves in the vacuum lines, which are responsible for control:
- The EGR valve (3 valves for vacuum, purge and control);
- Inlet manifold damper (2 valves for partial and full closure)
- Vortex flaps (variable swirl control)
- Turbine geometry (variable boost control)
The valves are unreliable and if they fail, the engine will immediately start to malfunction. Most often the problem can be corrected by replacing the broken valve.
The restyled RF7J motor received half as many vacuum lines and solenoids for a simple reason: many vacuum actuators were replaced by electronic ones. For example, the choke damper and EGR valve received an electric servo actuator.
EGR valve features
From time to time this valve jams (cause – soot deposits), which makes it necessary to clean it. The fact that cleaning is necessary is signaled by weak engine traction, power unit trojan, smoking with a strong smell of diesel fuel, sometimes the engine may not even start. It is noteworthy that sometimes such symptoms are floating, no errors appear.
Is the intercooler unreliable?
The intercooler is equipped with unreliable aluminum flanges, which crack after 200 thousand kilometers. The cracks are small, and there are no special problems with leaks of inflated air. But through the cracks, oil seeps outward and ends up on the left fender and driver’s door. It is possible to drive with such a problem, but it is recommended to replace the intercooler with a serviceable one.
What turbines are used in the engine?
The engine has received Japanese turbines IHI. Common Rail diesels were equipped with the following variable geometry turbines:
- IHI RHF4 VJ32 on the RF5C.
- IHI RHV4V VJ36 on RF7J.
The turbos last a long time, their main problems are the geometry damper wedge or the actuator stem itself. The vacuum tube that controls the geometry actuator has a vacuum chamber on it that looks like a small barrel. If it loses its seal, there are problems with the turbine’s geometry operation.
It is not uncommon for the IHI turbine on a Mazda diesel to under-inflate, resulting in significantly reduced engine power and thick black smoke from the exhaust. Rarely, the turbine leaks oil: oil can leak outward, and at the same time get into the intake manifold. But such a malfunction can lead to serious consequences for the engine.
Special features of sealing washers under the injectors
The engines use Common Rail injectors installed on copper refractory washers. Their condition must be monitored, because due to burned washers, gases from the combustion chamber will end up under the valve cover. In addition, hot bursting gases can cause the death of the power unit, when they mix with engine oil, deteriorate its properties, which causes the formation of carbon deposits. Oil clogs the channels and clogs the oil pump screen, causing the engine to wedge, rotate the liners, and sometimes even tear off the connecting rod. Among the first to give up is the fourth knee or connecting rod.
The fact that the washer burns out is signaled by heavy smoke from the oil filler neck (in the open position), as well as pneumatic tsokaniya, which can be heard when the engine is running. Also, problems with washers are signaled by high oil consumption, which does not flow out, but is deposited in the cylinder head or oil channels.
With burned-out copper washers, the injectors also play when the engine is running.
The features of the fuel injector
The engine received a reliable Denso fuel injector, with which there are practically no problems. It can be killed only by dirty fuel, but, most likely, the injectors will be the first to require replacement or cleaning.
In case of malfunctions in the engine operation, it is necessary to pay attention to the fuel injector in the last turn. The SCV, injectors or the described gear on the camshaft are more likely to fail.
Special features of the SCV valve
Pre-restyled motors received a slightly larger SCV valve than restyled models. The engines are electromechanical valves, with solenoids and return springs that control the position of the core.
The solenoid is reliable, but its core and seat periodically fail: they develop wear.
Service life of the SCV valve is more than 150 thousand kilometers. If it fails, the valve should be replaced and calibrated.
Reverse fuel lines
In the Mazda 2.0 MZR-CD engine, they are installed under the valve cover. They have been known to leak fuel, and there are leaks of sealing washers in the connections, causing oil to get into the fuel. If leaks occur, the washers on the return tube will need to be replaced, and it is also recommended that the tubes and clamps be replaced.
Are the injectors reliable?
The motor has received reliable injectors, but they are not repairable. When the stem and cone of the atomizer needle are worn, there is a strong fuel drain into the return. The problem is signaled by ignition miss errors in cylinders with pouring injectors.
The first models of the pre-restyling RF5C engine received Denso injectors with calibration resistors in the cables. These were not calibrated by the ECU, they must be matched with resistors with the correct resistance. Replacement injectors can be purchased complete with a cable with the correct resistor.
When ordering a used Denso injector for this motor, then choose an injector with the correct resistor cable. Twenty-five pairs of Denso injectors and their cables were produced. After purchase and installation, the injectors need to be calibrated using the control box on the running motor. Both a branded scanner and a Chinese scanner are suitable for starting the procedure.