EP6 engine: specifications, description, problems, reviews

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EP6 engine: specifications, description, problems, reviews
EP6 engine: specifications, description, problems, reviews

The EP6 car engine is mainly installed in French cars from Citroen and Peugeot. Despite the fact that this power unit is quite common, it is imperfect and has a number of problems. In order to avoid them, it is necessary to follow a number of rules and recommendations for the operation and maintenance of the EP6 engine.

At a Glance

The EP6 power unit was developed jointly by Peugeot and BMW. Despite this fact, the engine turned out to be quite controversial: on the one hand, innovative technologies made it cheap, efficient and reliable, and on the other hand, it shows “capriciousness” to harsh operating conditions, which is expressed in excessive consumption of automotive oil. Nevertheless, the EP6 engine is installed not only on Citroen and Peugeot, but also on other models that are created by the BMW Group mega-concern.

ep6 engine
ep6 engine

It is worth noting that the company alsotook part in the development of the engine. The production of motors is carried out at the PSA Peugeot-Citroen plant. It is located in the northern part of France, and it is from there that the engines enter the world market. New developments and production technology of such units are kept in the strictest confidence. However, some of the information still seeps into the masses and becomes public.

For example, in this engine model, cylinders are installed, the heads of which are cast without the use of special molds. In addition, the manufacturer uses only light alloys as raw materials for the production of cylinder blocks. Another feature is the absence of a counterweight when balancing the crankshaft during the production of the motor. In the latest technology, the production of connecting rods is not complete without double-sided forging. After the engine is assembled, it goes through very strict quality control. This is probably what made this motor one of the most reliable in operation.

Engine specifications

This unit is equipped with four cylinders, as well as a special water cooling system. Engine power EP6 - 120 HP. With. (translated into electrical units - 88 kW), while the volume is 1598 cubic centimeters (or 1.6 liters). Each engine cylinder has 4 valves, their total number is 16. A distinctive feature is the compression ratio, which has a parameter of 11: 1. Many motorists can also be pleased with the torque, which is 160 Nm at 4250 rpm. The diameter of each cylinder is 77mm.

ep6 engine problems
ep6 engine problems

The EP6 engine pairs beautifully with a five-speed manual transmission as well as a four-speed adaptive transmission. In addition to the 120-horsepower version, there is a 150-horsepower version equipped with a turbocharger.

Engine device

Description of the EP6 engine device will allow you to better understand the cause of the malfunction and carry out prompt repairs. So, the power unit consists of the following parts:

  • four cylinders lined up;
  • two camshafts that are located in the cylinder head;
  • four valves per cylinder;
  • a special system that allows you to change the gas distribution phases;
  • BorgWarner Twin-Scroll turbocharger;
  • system that allows regular self-cooling of the turbocharger;
  • intercooler;
  • Timing chain drive;
  • hydraulic bearings and roller tappets that drive each valve;
  • direct injection systems.
ep6 engine
ep6 engine

Thanks to the above devices and mechanisms, the EP6 engine is considered one of the most high-tech and modern power units. At the same time, it is quite environmentally friendly, it is powered by RON 95-98 gasoline and complies with the EURO-4 environmental standard.

Main problems of the EP6 engine

According to statistics, the EP6 engine is installed on Peugeot more often than on other car brands. However, the owners of these carsoften complain about problems that arise with the motor. It is worth noting that EP6 is quite vulnerable to harsh operating conditions. Information on the causes of problems, as well as ways to resolve them, will be presented below.

On a brand new "Peugeot" or "Citroen" the engine starts to work quite noisy and unstable, while it does not "give out" the declared power. The motor literally chokes when trying to accelerate the car, while using an increased amount of oil and fuel. In addition, the phases of the gas distribution mechanism begin to “run away”, and a message may appear on the dashboard - antipollution system faulty…

peugeot ep6 engine
peugeot ep6 engine

It is inexplicable, but the fact is that on a new car with EP6, the sensor responsible for monitoring the temperature of the coolant begins to "fail", as a result of which the engine itself begins to work unstably. Incorrect sensor readings can lead to a wasted replacement of the thermostat, which will not solve the problem.

However, the main disadvantage of such a motor is quite frequent oil leaks. It can "escape" by seeping through the valve cover. From there, it enters the spark plug wells and corrodes the tips of the ignition coils there. Also, oil can leak from the oil filter housing, seep through the vacuum pump gasket and solenoid valve.

Causes of EP6 problems

The reasons that lead to a number of malfunctions and breakdowns of EP6 include the followingfactors:

  • Failure to follow the recommendations for the operation and maintenance of the engine.
  • Using the engine in harsh environments (constant high intensity operation, sudden temperature changes, high humidity, extreme driving).
  • Infrequent oil changes and use of poor quality fuel.

The last problem of the EP6 engine is worth talking about in more detail. A rare change of lubricant or operation of the EP6 motor in conditions of a low oil level leads to a breakdown of the mechanism responsible for lifting the valves. In this case, both the motor that moves the shaft, and the worm drive and the shaft gear may fail (mechanical wear of these elements simply occurs). Also, special attention should be paid to the period of use of the gas distribution chain. It stretches over time and needs to be replaced.

engine ep6 120 hp
engine ep6 120 hp

An interesting feature is the fact that Peugeot engineers recommend changing the oil after 20,000 kilometers of driving. This recommendation is aimed at the fact that after the expiration of the warranty period, the motorist will have a motor that requires serious overhaul: a stretched chain, displaced phases, oil channels clogged with slag, affected phase regulators, faulty sensors and much more. Well, where to overhaul the engine if not at the Peugeot service center?

This is what is being calculated at the stage of creating the power unit. It's just marketing and maximizing profit -nothing personal. Among other things, an error may appear on the dashboard of the car, which informs that the mixture is too rich. The main cause of this error is dirty oil passages (P2178 is the code for this error).

Troubleshooting for EP6 powertrain

In order to eliminate any malfunction that has arisen in the motor, it is necessary to know its exact signs and location. EP6 engine problems and solutions are described in the table below.

EP6 engine failure The way to fix it
Deposit on the engine valves occurs due to wear of the valve stem seals. They let oil through, which gets on the cylinders and burns, forming a thick soot, because of which the catalyst can fail. Ultimately, worn caps are affected, and they fail altogether. Carbon impairs gas distribution, and also interferes with the efficient and stable operation of the cylinders. As a result, the power unit cannot develop the declared power and chokes when trying to accelerate the car. In order to remove carbon from the valves, it must be cleaned manually. Well, if the problem is detected at an early stage, then the valve stem seals can be replaced with new ones. It is worth noting that this step will be a more economical solution than the subsequent overhaul of the EP6 power unit.

Excessive oil consumption. The main reason for thismay be a torn oil separator membrane, which is located in the valve cover.

The only true solution to this problem is to replace the valve cover. The thing is that Chinese repair kits do not have the appropriate quality, but original spare parts can be purchased both at official dealerships and in a number of reputable auto shops.
Phases of the gas distribution mechanism "float": the problem may lie either in an extended chain or in the failure of the "stars" of the phase regulators, camshafts and (or) valves that are responsible for supplying oil to the shafts. To fix the problem, depending on its cause, it is necessary to: replace the chain and tensioner, change the "stars", clean the oil channels in the gas distribution mechanism itself, or carry out all of the above operations at the same time.

The unstable operation of the power unit lies in the lack of oil, largely due to the fact that the timing mechanism is too complicated and literally "stuffed" with a number of complex components.

Check the oil level and maintain it as required.

Engine Sensors

The 5FW EP6 engine is equipped with a range of sensors that allow you to monitor its operation and detect malfunctions at the first sign. The following sensors are installed on the motor:

  • monitoring oil pressure;
  • detonation;
  • pulses;
  • oxygen;
  • watching coolant temperature;
  • thermostat;
  • adjusting the position of the camshaft.
citroen c4 ep6 engine
citroen c4 ep6 engine

Perhaps the main electronics of the motor is the switch, as well as the clutch actuator. These EP6 engine sensors help control the powertrain.

For the stable functioning of the sensors, it is necessary to carry out regular maintenance of the vehicle. In addition, it is worth monitoring the condition of the mechanical components and assemblies of the motor, as well as the quality and level of automotive oil. In case of failure of the sensors, they should be replaced immediately, as incorrect readings can lead to more serious damage. It is worth adding that any intervention in the EP6 motor systems should be carried out electronic debugging, which can only be performed by professionals with special equipment.

Engine resource

With proper care, the EP6 engine on the Citroen C4, as well as on the Peugeot, is capable of running back about 150-200 thousand kilometers. In order for the motor to remain in a "viable" state even after reaching these indicators, a number of rules and recommendations must be observed:

  • It is necessary to change engine oil every 8-10 thousand kilometers, while paying attention to its brand (in particular, TOTAL 5w30 ENEOS is recommended). It is also worth monitoring the quality of fuel (AI 95-98).
  • Need to develop the habit of regular technical inspectionsand complete vehicle diagnostics. Yes, this step takes time and does incur some cash costs, but they will be much larger when the engine is overhauled.
  • Worn and close to wear parts should be replaced immediately.
  • It is worth paying close attention to the condition of the engine sensors. It is they who inform about the stability of the motor, as well as the occurrence of possible malfunctions and breakdowns.

By adhering to the above recommendations, you can extend the life of the EP6 engine by a good 50-100 thousand kilometers. Perhaps such a unit will "eat" a little more oil, but at the same time the motor will work stably and efficiently.


According to car owners, the performance of the engine meets all modern requirements for engines. However, some note that it is systematically necessary to change the coolant temperature sensor. Also on the Web there are complaints about the noise that the engine makes during intensive work. Some notice a distinct audibility of the engine in the car. However, the declared service life of the engine is working properly. Despite this, the reliability of this mechanism remains in question.


The EP6 engine in Peugeot, Citroen, Mini Cooper and other car models is very popular. This demand is explained by the fact that the motor is quite high-tech, efficient, meets European environmental standards, and also has quite decent powercharacteristics. There are versions of 120 and 150 liters. The engines are quite reliable. This is due to the fact that they were created jointly by specialists from Peugeot and BMW.

ep6 engine device
ep6 engine device

With all the advantages of the engine, its disadvantage is "capriciousness" both to the quality of fuel and oil, and to operating conditions. The motor for stable operation requires increased attention: regular diagnostics and maintenance will increase the life of the engine. For example, oil must be changed every 10 thousand kilometers, instead of the 20 declared by the manufacturer, and candles must be replaced after 25 thousand kilometers of car run. After the engine "runs" 50 thousand kilometers, you should think about conducting a complete diagnosis of the power unit and manipulations to eliminate the problems that have arisen. Thanks to timely diagnostics and maintenance, as well as the use of high-quality fuel and oil, the engine is able to work about 200 thousand kilometers without serious problems. In general, the resource of the unit is 300-350 thousand km.