Radiator cap in Nissan Murano Z50 - a small but critical detail on which the stability of the entire cooling system depends. Many owners pay attention to oil, filters or brake pads, forgetting that a faulty cover can lead to engine overheating, ruptured pipes or even deformation of the cylinder head. In this article we will look at how to choose the right cover for Murano Z50, what to look for when purchasing, and why replacing it sometimes solves problems with “boiling” antifreeze.

Model Z50 (2015–2021) equipped with gasoline engines VQ35DE (3.5 l) and hybrid options, where the cooling system operates under high pressure. The radiator cap here performs two key functions: it maintains pressure within 1.1–1.3 bar and releases its excess through the valve. If it fails, the consequences can be costly - from an antifreeze leak to a major engine overhaul.

Signs of a bad radiator cap

How to tell if the radiator cap is Nissan Murano Z50 needs replacement? Symptoms are often disguised as other problems, but there are characteristic “bells”:

  • 🔥 Engine overheating for no apparent reason (the fan is running, the antifreeze is normal, but the temperature rises higher 90°C).
  • 💦 Antifreeze leak from under the cap or through the expansion tank - a sign that the valve does not hold pressure.
  • 🌀 Steam from under the hood after stopping the engine, excess pressure “pushes” the fluid through weak points.
  • 🛠️ Deformation of pipes (they become hard or swell) - a consequence of constant pressure surges.

One of the most insidious symptoms is air pockets in the cooling system. They occur when the cover does not bleed air when the engine cools, which leads to uneven heating of the interior or a “cold” heater when the engine is hot. If you notice that the temperature on the dashboard is fluctuating and the radiator pipes are cold, the first thing to do is check the cap.

⚠️ Attention: Do not confuse a malfunctioning cover with a broken thermostat or pump. For example, if the antifreeze goes away, but there are no signs of leakage, the problem may be microcrack in the expansion tank — it is visible only when the engine is running under pressure.

How to check the radiator cap for functionality

You can carry out diagnostics yourself, without resorting to the help of a service station. You will need: gloves, rags and pressure test pump (or even a regular bicycle pump with a pressure gauge). Algorithm of actions:

  1. Visual inspection. Check the cover for cracks, corrosion or damage to the rubber seal. If the seal becomes dull or crumbles, the cover must be replaced.
  2. Valve check. Remove the cover from a cold engine and shake it - if you hear the sound of rolling balls, the valve is most likely good. The absence of sound indicates a jam.
  3. Leak test. Place the cap on the radiator, close the drain valve (if equipped) and build up pressure with the pump. Normal: the lid should open when 1.1–1.3 bar. If the pressure drops or the cap “shoots” earlier, it is faulty.

For more accurate diagnosis, you can use cooling system tester (For example, OTC 3633 or analogues). It simulates the operation of the system under load and shows whether the cap holds pressure. If you don’t have a tester, pay attention to the behavior of the antifreeze: when the engine is running, it should not “bubble” in the expansion tank - this is a sign that the valve is not releasing excess pressure.

📊 How often do you check the cooling system of your Nissan Murano?
  • Once a year
  • Only when problems arise
  • Never checked
  • Every 10,000 km

Which radiator cap to choose for Nissan Murano Z50

Original radiator cap for Murano Z50 has an article number 21411-4M000 (or 21411-4M00A for some markets). It is designed for pressure 1.1 bar and is equipped with a two-level valve (inlet and outlet). However, there are worthy analogues on the market, which are often not inferior in quality, but are cheaper.

Manufacturer Article Pressure, bar Price, ₽ Features
Nissan (original) 21411-4M000 1.1 1 800–2 500 Guaranteed compatibility, long service life
Gates 31039 1.1 800–1 200 High-quality rubber resistant to high temperatures
Febi 10621 1.1 600–900 A good budget option, but there are fakes
Hepu P90-11 1.1–1.3 1 000–1 400 Reinforced valve, suitable for tuned engines

When choosing an analogue, pay attention to seal material - it must be made of heat-resistant rubber (for example, EPDM). Cheap lids with silicone seals quickly become dull and begin to leak antifreeze. Also check if the valve has spring — without it, the lid will not be able to regulate pressure correctly.

⚠️ Attention: Covers from other models Nissan (For example, X-Trail T32 or Qashqai J10) may be externally suitable, but have a different operating pressure. Using such a cover will result in rupture of pipes or damage to the radiator.
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Before purchasing, compare the new lid with the old one - they must match in height, diameter and valve location. Even a slight difference can result in a loose fit.

Step-by-step instructions for replacing the radiator cap

Replacing the radiator cap with Nissan Murano Z50 takes no more than 10 minutes, but requires care. Main rule: carry out all work on a cold engineto avoid burns from hot antifreeze. You will need:

  • 🔧 New radiator cap (trusted manufacturer).
  • 🧤 Gloves (antifreeze is toxic!).
  • 🧴 Rags or paper towels.
  • 🔦 Flashlight (for inspecting pipes).

Sequence of actions:

  1. Release the pressure. On a cold engine, slowly turn the cap counterclockwise until it clicks (do not open all the way!). This relieves excess pressure. Then remove the cover completely.
  2. Inspect the radiator neck. Make sure there is no damage or deposits on the threads. If necessary, clean it with a soft brush.
  3. Install a new cover. Screw it tightly clockwise until it stops. Do not apply excessive force - just finger-tighten.
  4. Check the system. Start the engine, warm it up to operating temperature and make sure that the antifreeze does not boil and the pipes do not swell.

The engine has completely cooled down (wait at least 2 hours after the trip)|

I have a new cap with the correct part number on hand|

The pipes have been checked for cracks or swelling|

A container has been prepared for draining antifreeze (in case of leakage) -->

If the overheating problem persists after replacing the cover, check:

  • 🔍 Antifreeze level (must be between MIN And MAX on a cold engine).
  • 🔄 Thermostat operation (when warming up, the upper radiator hose should heat up).
  • 💨 Cooling fan (it should turn on at temperature ~95°C).

Common replacement errors and their consequences

Even something as simple as replacing a radiator cap can turn into problems if mistakes are made. Let's look at the most common ones:

  1. Replacement on a hot engine.

    The antifreeze in the system is under pressure, and when the cap is opened, it can escape in a stream of temperatures up to 120°C. Consequences: burns, splashing of toxic liquid, damage to the paintwork under the hood.

  2. Using a cap with a different pressure.

    For example, installing a cover on 0.9 bar (from Nissan Almera N16) will cause the antifreeze to boil at a lower temperature, and the pipes will wear out faster.

  3. The lid is not screwed tightly.

    If the cap is not tightened, the system is not sealed and antifreeze will evaporate through micro-gaps. This will lead to constant drop in coolant level and the risk of overheating.

  4. Ignoring verification after replacement.

    Many people install a new cover and forget to check its operation. Meanwhile, defective valves are found even in well-known brands (for example, Febi or Blue Print).

To avoid errors, after replacing the cover, perform test drive: Drive 5-10 km while monitoring the engine temperature. If the needle rises above normal, stop and check:

  • 🔥 Do both radiator pipes heat up (if one is cold, there is a problem with the thermostat).
  • 💨 Does the cooling fan turn on (if not, check the fuse or temperature sensor).
  • 💦 Are there any antifreeze leaks under the lid or on the connections.
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If, after replacing the cap, the antifreeze continues to leak, but there are no signs of leakage, the problem may be broken cylinder head gasket or a crack in the cylinder block. In this case, an in-depth diagnosis is required.

Cooling System Maintenance: How to Extend the Life of Your Radiator Cap

Radiator cap service life Nissan Murano Z50 amounts to 3–5 years or 60,000–80,000 km, but it may be reduced due to aggressive use or low-quality antifreeze. To avoid premature wear:

  • 🔄 Change antifreeze every 5 years (or 90,000 km). Old fluid loses its properties and becomes aggressive towards rubber seals.
  • 🧪 Use only recommended antifreeze - for Murano Z50 this is Nissan Coolant L255N (green) or its analogues (CoolStream A-110, Sintec Unlimited G12++).
  • 🚗 Avoid sudden loads on a cold engine - this creates pressure surges that destroy the lid valve.
  • 🔍 Inspect the cooling system regularly for leaks, swollen pipes or corrosion on the radiator.

Pay special attention flushing the system when replacing antifreeze. B Murano Z50 Deposits often accumulate in the radiator and engine block, which impair fluid circulation. For washing, you can use special products (for example, Liqui Moly Kuhler-Reiniger) or distilled water with citric acid (100 g per 5 l).

What happens if you ignore replacing the cover?

Driving for a long time with a faulty radiator cap leads to:

  1. Engine overheating — risk of deformation of the cylinder head (repair will cost 50 000–150 000 ₽).
  2. Rupture of pipes - swelling on the connecting hoses is especially dangerous (replacing them costs 3 000–8 000 ₽ per set).
  3. Radiator damage - aluminum honeycombs cannot withstand constant water hammer, and the radiator begins to leak (the price of a new one is from 15 000 ₽).
  4. Antifreeze getting into the oil — if the cylinder head gasket is broken, the consequences are fatal (engine overhaul).

Answers to frequently asked questions

Is it possible to drive without a radiator cap?

No, this is extremely dangerous. Without a lid, the cooling system is not sealed; the antifreeze will boil when ~90°C (instead of 110–120°C with a cover), and the engine will overheat in a few minutes. In addition, when driving, antifreeze will splash out of the radiator.

What is the difference between a radiator cap and an expansion tank cap?

On Murano Z50 radiator cap regulates pressure in the system (designed for 1.1 bar), and the expansion tank cap simply protects from dust and fumes. They cannot be confused: if you put the reservoir cap on the radiator, the system will not hold pressure and the antifreeze will boil.

How often should you replace your radiator cap?

The manufacturer does not establish strict regulations, but it is recommended to check its condition every 30,000 km or once every 2 years. Signs for replacement: cracks, loss of elasticity of the seal, pressure incontinence (checked with a pump).

Can I use the cover from the Nissan X-Trail T32?

No, despite the external similarity, the lids have different operating pressures. For X-Trail T32 (article 21411-4M01A) it amounts to 1.3 bar, and for Murano Z50 — 1.1 bar. Installing a cap with a higher pressure will increase the load on the pipes and radiator.

Why does antifreeze still leave after replacing the cap?

The reasons may be as follows:

  1. Leakage of the system (cracks in the radiator, pipes or expansion tank).
  2. Failure of the cylinder head gasket (antifreeze goes into the oil or exhaust gases).
  3. Defective new cover (found in cheap analogues).
  4. Airing of the system (antifreeze needs to be pumped).

Check the oil level - if there is an emulsion (light foam) on the dipstick, this is a sign of antifreeze getting into the engine.