Filter Nissan 23731-4M50B is not just a consumable, but a critical element of the fuel system of diesel engines Nissan, on which the life of injectors, high-pressure pumps and even turbines depends. Its original version is designed specifically for models with motors M9R (2.0 dCi) and R9M (1.6 dCi) installed on Qashqai J10/J11, X-Trail T31/T32, Navara D40 and others. However, the market is in chaos: branded counterfeits Nissan occur in 3 out of 5 cases, and cheap analogues often do not withstand even half of the declared resource.

In this article we will not just list the characteristics of the filter, but will analyze a unique problem with corrosion of the metal body of counterfeit products, which leads to rust getting into the fuel line. You will learn how to distinguish an original from a fake by 3 external signs, why the filter requires replacement every 20–30 thousand km (instead of the declared 40 thousand), and which analogues are actually not inferior to the branded one Nissan. And also - instructions for replacement with photographs of key stages and an analysis of typical errors due to which the new filter fails within a month.

Where is filter 23731-4M50B used: complete list of models and engines

Filter Nissan 23731-4M50B installed on diesel cars of the concern Renault-Nissan with injection systems Common Rail. Its direct analogues are Renault 8200813237 And Samsung SM5 23731-4M500 (for Korean market). Below is a complete list of models where this filter is used as standard:

  • 🚗 Nissan Qashqai J10/J11 (2007–2021) - engines M9R 2.0 dCi (150/175 hp) and R9M 1.6 dCi (130 hp)
  • 🚙 Nissan X-Trail T31/T32 (2007–2020) - the same engines, including versions with all-wheel drive 4x4-i
  • 🛻 Nissan Navara D40 (2005–2015) — M9R in modifications for Europe and the Middle East
  • 🚐 Renault Koleos I/II (2008–2020) - complete analogue X-Trail T31 by fuel system
  • 🚘 Samsung SM5 (2005–2013) - Korean version Teana with diesel M9R

Important: filter doesn't fit for gasoline engines Nissan (For example, MR20DD or HR16DE), as well as for diesel engines older than 2005 with pump injectors. If your car was manufactured before 2007, it most likely uses a different type of filter - Nissan 16400-JD00A.

⚠️ Attention: On Nissan Pathfinder R51 (2005–2012) with motor V9X 2.5 dCi a filter is installed 23731-4M51A - it is similar in appearance, but has a different backflow valve. Installation 23731-4M50B instead it will lead to problems with cold starting.
Model Engine Years of manufacture Notes
Qashqai J10 M9R 2.0 dCi 2007–2013 Filter assembly with water sensor
X-Trail T32 R9M 1.6 dCi 2014–2020 Requires adaptation after replacement
Navara D40 M9R 2.5 dCi 2005–2015 Version for markets with low quality diesel fuel
Renault Koleos I M9R 2.0 dCi 2008–2013 Identical X-Trail T31

Original vs fake: 5 signs that indicate counterfeit

According to Nissan Russia, up to 60% filters 23731-4M50B on the Russian market - fakes. Their main danger is not low filtration efficiency (although this is critical), but corrosion of the internal metal casing, which begins after 3–6 months of operation. Rust particles clog the injectors and cause them to fail. injection pump (high pressure fuel pump). Below is a checklist for checking originality:

  • 🔍 Packing: Original box Nissan has a holographic sticker with a serial number, which can be checked on the website Nissan Genuine Parts. Counterfeits often come in plastic bags without a hologram.
  • 🏷️ Marking: Embossed on the original filter: NISSAN 23731-4M50B, brand logo, country of origin (Japan or Spain). On fakes, the inscriptions are blurry, and the letter “B” at the end of the article is often missing.
  • 🔧 Thread and plastic: The original filter has metal thread on the inlet/outlet fitting, and the plastic body is matte, without burrs. Counterfeits often have plastic threads that break when tightened.
  • 💧 Water sensor: In the original, the sensor is built into the housing and is marked DENSO. In fakes it is either absent or made as a separate part.
  • 📦 Equipment: There is always an O-ring in the box with the original Nissan 16515-4M500 and instructions in 3 languages (including Russian). Counterfeits often come without a ring.

The most reliable way to check is to weigh the filter. The original weighs 380–400 grams, and fakes - 250–300 grams due to the thinner metal of the case. Also note filter element color: the original is gray-white, the fakes are yellow or green.

📊Have you ever bought fake parts for Nissan?
  • Yes, by mistake
  • Yes, specially (cheaper)
  • No, I always take the original
  • I don't know how to tell the difference

Resource and replacement frequency: why the official 40 thousand km is a myth

In the manuals Nissan filter replacement interval indicated 23731-4M50B — 40 thousand km. But this indicator is relevant only for Europe, where the quality of diesel fuel meets the standard EN 590. In Russia, Ukraine and the CIS countries, the actual filter resource is reduced by 1.5–2 times due to:

  • 🛢️ High sulfur content (up to 10 ppm versus 50 ppm in the EU), which accelerates the oxidation of the paper filter element.
  • 🌡️ Temperature changesleading to condensation in the fuel tank and water entering the system.
  • 🚜 Fuel dust content at “second-tier” gas stations, where storage filters have not been changed for years.

Service station practice shows: during mileage 30–35 thousand km the filter is already clogged by 60–70%, which leads to:

  • 🔥 Increased load on injection pump (risk of overheating and failure).
  • ⚡ Pressure drop in the fuel rail (errors P0087 or P0190).
  • 💨 Increased soot formation (clogs DPF or EGR).

Recommendations for replacement depending on operating conditions:

Terms Replacement interval Signs of wear
City (quality diesel fuel) 25–30 thousand km Difficulty starting when cold
Suburb/highway 30–35 thousand km Loss of power at high speeds
Extreme conditions (dust, low temperatures) 20 thousand km Frequent errors in the fuel system
⚠️ Attention: If after replacing the filter the car does not start or runs intermittently, check installation direction. There is an arrow on the original filter housing FLOW, indicating the direction of fuel movement. Installation "back to front" leads to reverse current of the diesel engine and failure injection pump for 1–2 launches.

Step-by-step replacement instructions: how to avoid mistakes

Replacing the filter 23731-4M50B on Qashqai or X-Trail takes 30–40 minutes, but requires care. The main difficulty is Bleeding pressure in the fuel systemto avoid splashing of diesel fuel. You will need:

  • 🔧 10 mm wrench (for clamps)
  • 🔩 17 mm socket wrench (for drain plug)
  • 🧴 Container for draining fuel (at least 0.5 l)
  • 🧼 Rags and cleaning agent WD-40

Step-by-step algorithm:

  1. Release the pressure: Open the hood, locate the fuse box, and remove the fuel pump fuse (usually F15 15A). Start the engine and let it run until it stops (it will burn out any remaining fuel).
  2. Drain the fuel: Place a container under the filter, unscrew the drain plug (bottom bolt 17 mm) and wait until the diesel fuel is completely drained.
  3. Remove the old filter: Loosen the clamps on the inlet/outlet hoses (10 mm wrench) and carefully remove them. Unscrew the filter mount to the body (10 mm bolt).
  4. Install a new filter: Transfer the O-ring from the old filter (or use the new one from the kit). Connect the hoses following the direction of the arrow FLOW.
  5. Bleed the system: Insert the pump fuse, turn the ignition on for 30 seconds (the pump will pump fuel), then start the engine. It may work intermittently for the first 1-2 minutes - this is normal.

Check the tightness of the hose connections|

Make sure the drain plug is tight|

There are no errors in the fuel system (check with a scanner) |

Rail pressure of at least 300 bar (with engine running) -->

Typical replacement mistakes:

  • 🚫 Ignoring leveling: If the pump is not allowed to fill the system, air pockets will lead to unstable engine operation.
  • 🚫 Re-stretching clamps: Plastic filter fittings break with a force of more than 2 Nm.
  • 🚫 Using an old O-ring: It becomes tanned over time and does not provide an airtight seal.
💡

If after replacing the filter the engine does not start, check the voltage at the fuel pump (pin 2 on the connector). If there is no 12V, the problem is with the relay or fuse, not the filter.

The best analogs of 23731-4M50B: what to choose if there is no original

Original filter Nissan costs 1,800–2,500 rubles, but it is often out of stock. There are worthy analogues on the market that are not inferior in filtration quality, but are 30–50% cheaper. The main thing is to avoid “no-name” brands (for example, Patron or Big Filter), which are not certified ISO/TS 16949.

Top 5 proven analogues:

Brand Article Price, rub. Features
Mann Filter PU 9002 Z 1 200–1 500 Best filtration (98% for 4 micron particles)
Bosch F 026 402 007 1 300–1 600 Reinforced housing, suitable for harsh conditions
Mahle KX 338/2 D 1 400–1 700 Comes with a new O-ring
Framm P9636 900–1 200 Budget option, but the resource is 20% lower
SCT ST 393 800–1 000 Suitable for temporary replacement (lifetime up to 15 thousand km)

If you choose between Mann And Bosch, pay attention to climatic conditions:

  • 🌡️ For regions with frosts below -30°C it is better Bosch — its body can withstand temperature changes without cracking.
  • 🏙️ Optimal for urban use Mann — it filters soot and small particles better.
⚠️ Attention: Filters Framm P9636 And SCT ST 393 do not have a built-in water sensor. If your fuel system had it, after installing these analogues an error will appear on the dashboard Check Engine (code P0183). To eliminate it, you will have to turn off the sensor programmatically via Nissan Consult.

Common problems after replacing the filter and how to fix them

Even if you installed the original filter 23731-4M50B, malfunctions may occur. Let's look at typical symptoms and their causes:

  • 🔴 The engine does not start:
    • 🔹 The pressure in the system has not been released (repeat the procedure for draining the fuel).
    • 🔹 Air lock (bleed the system as described above).
    • 🔹 The fuel pump is faulty (check the voltage at the connector).
  • 🟡 The engine stalls or runs intermittently:
    • 🔹 The filter is installed backwards (check the direction of the arrow FLOW).
    • 🔹 O-rings are damaged (replace with new ones).
    • 🔹 Dirt got into the fuel during replacement (rinse the system).
  • 🔵 Error P0183 (high level of water sensor signal):
    • 🔹 The water sensor is not connected or damaged (check the connector).
    • 🔹 There is indeed water in the filter (drain the fuel from the tank).

If after replacing the filter there is noise from fuel pump, this may indicate:

  • 🔊 Clogged coarse mesh in the tank (requires cleaning or replacement Nissan 17040-JD00A).
  • 🔊 Wear of the pump itself (check the pressure with a pressure gauge - it should be 3.5–4 bar).
What should I do if the “Check Engine” light comes on after replacing the filter?

1. Connect a diagnostic scanner (for example, Launch CReader) and read the error code.

2. If there is an error P0087 (low fuel rail pressure), check:

- Tightness of hose connections (air leaks).

- Operation of the pressure regulator (valve on the ramp).

3. If there is an error P0190 (pressure sensor circuit malfunction), replace the sensor (Nissan 22630-4M500).

4. After eliminating the cause, reset the error via a scanner or by disconnecting the battery for 10 minutes.

How to extend the life of the fuel system: 5 tips from service station specialists

Filter 23731-4M50B - this is only part of the system, and its resource depends on the general condition of the fuel line. To avoid costly repairs injection pump or injectors (the price of a new set is from 80 thousand rubles), follow these recommendations:

  1. Use diesel additives once every 5 thousand km. Best options:
    • 🧪 Liqui Moly Diesel Systempflege — cleans the injectors and increases the cetane number.
    • 🧪 Wynn's Diesel Injector Cleaner - removes deposits in injection pump.

    ❌ Do not use alcohol-based additives - they destroy rubber seals.

  2. Drain the sediment from the tank every 10 thousand km. Water and dirt accumulate at the bottom of the tank, which the filter does not retain. For draining:

    1. Поднимите заднюю часть автомобиля (или загоните на яму).

    2. Открутите сливную пробку бака (ключ на 17 мм).
    

    3. Слейте 200–300 мл топлива в прозрачную ёмкость — если есть осадок, промойте бак.

  3. Refuel at trusted gas stations. Use apps like "Gas station of Russia" or "GasAll", where users leave reviews about the quality of fuel. Avoid gas stations with a price lower than the regional average by 2-3 rubles - diesel fuel is often diluted there.
  4. Check the fuel rail pressure once every 20 thousand km. Normal indicators:
    • 📊 Idling: 300–350 bar.
    • 📊 At 2,000 rpm: 400–500 bar.

If the pressure is lower, the problem is injection pump or regulator.

  • Change the air filter along with fuel. A clogged air filter increases the load on the engine, which leads to increased fuel consumption and rapid clogging 23731-4M50B.
    • 💡

    The most common cause of premature filter failure 23731-4M50B — refueling with fuel with a high paraffin content in winter. If diesel fuel “freezes” in the tank, the filter element becomes clogged with paraffin crystals within a few hours. Use an antigel (for example, Castrol TDA) at temperatures below -15°C.

    FAQ: Answers to frequently asked questions

    🔧 Is it possible to wash filter 23731-4M50B instead of replacing it?

    No, washing will not restore its properties. The filter element is made of special paper with micropores that become clogged irreversibly. Flushing (even with ultrasound) can temporarily improve flow, but dirt particles will remain in the pores and continue to break down injection pump.

    Exception - emergency (for example, the filter became clogged on the way). In this case, you can carefully blow it out with compressed air (pressure no more than 2 bar), but after that be sure to install a new filter.

    🚗 Is filter 23731-4M50B suitable for Nissan Almera N16 with diesel?

    No, for Almera N16 (2000–2006) with engine YD22DDTi filter is used Nissan 16400-ED000 or its equivalent Mann WK 8002. The injection systems of these models are fundamentally different: Almera pump injectors, and Qashqai/X-Trail — Common Rail.

    💰 Why is the original filter 2 times more expensive than its analogues?

    Original price 23731-4M50B includes:

    • 🔹 Water sensor (often absent from analogues).
    • 🔹 Reinforced body made of stainless steel (cheap analogs have galvanized steel, which rusts).
    • 🔹 Guarantee from Nissan (when installed at an official service station).
    • 🔹 Logistics — the filter is supplied from Japan or Spain, while analogues are produced in China or Poland.

    However, it makes sense to overpay only if you operate the car in difficult conditions (dust, low temperatures, low-quality diesel fuel). There are enough filters for city driving Mann or Bosch.

    ⚡ What happens if you don’t change the filter on time?

    The consequences depend on the mileage after the filter has expired:

    • 🔹 30–40 thousand km: Power drop, diesel fuel consumption increase by 10–15%, errors P0087 (low rail pressure).
    • 🔹 50–60 thousand km: Wear injection pump (repair cost - 30-50 thousand rubles), ring jamming due to dirt getting into the cylinders.
    • 🔹 80+ thousand km: Failure of injectors (the price of one is 15–25 thousand rubles), destruction of the turbine due to metal particles.

    Critical case: if the filter is completely clogged, the engine stalls while driving due to lack of fuel. In this case it often breaks injection pump, since it runs dry.

    🔍 How to check that the filter is clogged without diagnostics?

    There are 3 reliable ways:

    1. Idle test: With the engine running, press the gas pedal sharply. If the speed rises slowly (with a delay of 1-2 seconds), the filter is clogged.
    2. <