CVT radiator <em>Nissan Murano Z51</em>: diagnostics, replacement and selection of spare parts

Nissan Murano Z51 with variator JF011E is a reliable crossover, but its transmission requires special attention to the cooling system. The variator radiator performs a critical function here: it maintains the operating oil temperature in the range 80–100°C, preventing overheating and premature wear of the belt. However, over time, this unit becomes clogged with wear products or loses its seal, which leads to expensive repairs.

Owners Murano Z51 (2015–2022) often encounter symptoms of a CVT radiator malfunction after 120–150 thousand km. At the same time, official dealers do not always correctly diagnose the problem, attributing jerks during acceleration to “variator wear.” In this article, we will look at how to independently identify problems, select a high-quality radiator (including analogues) and replace it without errors.

Signs of a faulty variator radiator

The first signals of problems with the variator radiator Nissan Murano Z51 often disguised as other faults. For example, jerks when switching may indicate both belt wear and oil overheating due to poor cooling. Let's look at the key symptoms:

• 🔥 CVT overheating: oil temperature exceeds 110°C (checked via diagnostic scanner or ELM327). The icon may light up on the dashboard AT TEMP.
• 🛢️ Darkening of the oil: When checked with a dipstick, the oil has a black tint and a burning smell - a sign that the radiator is not coping with cooling.
• ⚡ Jerks during acceleration: especially noticeable at speeds 40–60 km/hwhen the variator tries to compensate for belt slippage.
• 💧 Oil leaks: traces NS-3 (specific oil for variators Nissan) under the radiator or on the pipes.

It is important to distinguish these symptoms from malfunctions of the variator itself. For example, vibrations at idle are more often associated with the engine mounts rather than the cooling system. For an accurate diagnosis, it is recommended to check oil line pressure variator (standard: 4–6 bar at 2000 rpm).

⚠️ Attention: If metal particles are visible on the variator dipstick, the problem has already gone beyond the radiator - diagnostics of the valve body or belt is required. In this case, replacing the radiator without repairing the variator is pointless.

Design and location of the variator radiator

B Nissan Murano Z51 The variator radiator is integrated into the engine cooling system, but has a separate circuit. It is located in front of the main radiator (driver's side) and is connected to the variator by two metal tubes:

• 🔄 Inlet tube (from the variator to the radiator) - supplies hot oil.
• 🔙 Return tube (from radiator to variator) - returns cooled oil.

Design feature - no separate thermostat for the variator. Cooling is regulated by circulating antifreeze through a heat exchanger built into the radiator. This simplifies the system, but makes it vulnerable to clogging.

System element	Article (original)	Note
CVT radiator	21311-JK00A	Includes heat exchanger and mounting brackets
Inlet tube (variator → radiator)	21342-JK00A	Aluminum, often breaks during dismantling
Return pipe (radiator → variator)	21343-JK00A	Has rubber seals that require replacement
Radiator O-ring	21326-JK000	Be sure to change it every time you remove the radiator.

When replacing the variator radiator with Murano Z51 it is also recommended to update oil in the variator (article KLE52-00004 for NS-3) and flush the engine cooling system. This is due to the fact that radiator wear products can get into the antifreeze.

CVT radiator diagnostics: step-by-step instructions

Before replacing the radiator, it is necessary to confirm that it is faulty. Here is the verification algorithm for Nissan Murano Z51:

1. Visual inspection:
   • 🔍 Check the radiator for dents or corrosion (especially at the bottom).
   • 💦 Look for traces of oil NS-3 on the pipes and pipes - they have a reddish tint.
2. Temperature check:
   • 📊 Connect a diagnostic scanner (for example, Launch X431) and compare the temperature of the variator oil (CVT Fluid Temp) with antifreeze temperature (Coolant Temp). The difference is more 20°C indicates poor cooling.
3. Clogging test:
   • 🧪 Drain 100–150 ml oil from the variator. If the liquid contains metal shavings or it smells like burning, the radiator is clogged.

For accurate diagnosis you can use thermal imager (For example, FLIR ONE). A heated radiator should give off heat evenly. If one section remains cold, this is a sign of internal blockage.

Warm up the engine to operating temperature (90°C)|Prepare a diagnostic scan tool or ELM327|Prepare an oil drain container (minimum 1 liter)|Have a flashlight handy to inspect the bottom of the radiator-->

⚠️ Attention: Do not confuse the CVT radiator with the air conditioner radiator! They are located next to each other, but the variator radiator has metal tubes diameter ~20 mm, and the air conditioner is made of thin aluminum tubes.

Radiator selection: original vs analogues

Original variator radiator for Nissan Murano Z51 (article 21311-JK00A) is worth 12–15 thousand rubles (for 2026). However, there are high-quality analogues on the market that are cheaper. Below is a comparison table:

Manufacturer	Article	Price, rub.	Features
Nissan (original)	21311-JK00A	12 000–15 000	1 year warranty, fully compatible
Denso	DRH0124	8 500–10 000	Japanese quality, used on the assembly line Nissan
Koyorad	V4029	7 000–8 500	Reinforced tubes, suitable for harsh conditions
NRF	21311JK00A	6 000–7 500	Budget option, 6 month warranty

When choosing an analogue, pay attention to:

• 🔧 Tube material: Cheap radiators are often made of aluminum (instead of copper), which reduces heat transfer.
• 📏 Core thickness: the original has 38 mm, for some analogues - 30–32 mm, which impairs cooling.
• 🔄 Presence of pressure relief valve: in the original it is built into the upper pipe.

Critical moment: radiators from Nissan X-Trail T32 (article 21311-4M00A) are similar in appearance, but have a different tube diameter and are not suitable for Murano Z51! When installing such a radiator, the oil will overheat due to insufficient flow.

Step-by-step replacement of the variator radiator

Replacing the radiator with Nissan Murano Z51 You can do it yourself if you have the tools. Opening hours: 3–4 hours. You will need:

• 🔧 Set of heads (10 mm, 12 mm, 14 mm).
• 🛠️ Socket wrench for variator pipes.
• 🧰 Sealant Loctite 574 (for rubber seals).
• 🧴 Oil NS-3 (8–10 l for a complete replacement).

Work order:

1. Draining oil from the variator:
   • 🔧 Unscrew the drain plug on the variator pan (key 24 mm).
   • 💧 Drain the oil into a container (it will leak out ~4–5 l).
2. Radiator removal:
   • 🔨 Remove the front bumper and grille (6 bolts 10 mm).
   • 🔧 Disconnect the variator tubes (use a socket wrench so as not to tear off the edges!).
   • 🔩 Unscrew the 4 radiator mounting bolts (12 mm).
3. Installing a new radiator:
   • 🔧 Transfer the brackets from the old radiator to the new one.
   • 🧴 Apply sealant to the O-rings of the tubes.
   • 🔩 Tighten the mounting bolts to torque 22 Nm.
4. Oil refill:
   • 🛢️ Fill with new oil NS-3 through the variator dipstick (required ~8 l).
   • 🔄 Warm up the variator until 60°C and add oil to the level HOT on the dipstick.

After replacing the radiator, be sure to reset the variator adaptations via the diagnostic scanner (command CVT Learning). This will prevent jerking at first 50–100 km after repair.

What to do if after replacing the radiator the variator jerks?

This is a normal phenomenon in the first 50–100 km, as the variator “learns” new operating conditions. If the jerking does not disappear:

1. Check the oil level (should be between the marks HOT on a warm variator).

2. Make sure that the tubes are not pinched or kinked.

3. Reset adaptations via the scanner (command CVT Reset).

If the problem persists, there may be an assembly error or a defective radiator.

⚠️ Attention: When disconnecting the variator tubes, be prepared for something to leak out of them ~100–150 ml oils Prepare rags and a container to collect liquid in advance. Do not allow oil to get on the timing belt!

Prevention and increase in radiator life

The service life of the variator radiator is Nissan Murano Z51 can be extended by following simple recommendations:

• 🔄 Change the oil in the variator every 60 thousand km (instead of regulatory 90 thousand km). Use only NS-3 - other oils (for example, CVT Fluid NS-2) are incompatible!
• 🧴 Flush the radiator at every oil change. To do this, disconnect the return pipe and pump through the system 1–2 l fresh oil.
• 🚗 Avoid overheating:
  • Do not tow trailers weighing > 1 t.
  • Do not keep your foot on the brake on long descents (use L or S on the selector).
• 🔍 Inspect regularly radiator for damage (especially after off-road driving).

It is also recommended to install additional variator cooling radiator (For example, Setrab 920-760-740). This is relevant for regions with hot climates or when operating the machine in mountainous areas. Set cost: ~15 thousand rubles.

Common mistakes when replacing a variator radiator

Even experienced craftsmen make mistakes when working with the variator cooling system Nissan Murano Z51. Here are the most common:

• 🔧 Tubing: When tightening with a socket wrench, it is easy to tear off the edges on aluminum tubes. Use a torque wrench 25–30 Nm.
• 🧴 Not adding enough oil: after replacing the radiator, ~ remains in the system1–1.5 l old oil. If you do not take this into account when refueling, the level will be below normal.
• 🔄 Ignoring adaptations: Without resetting the settings, the variator will work in emergency mode, which will lead to jerking.
• 💧 Mixing antifreeze: When replacing the radiator, some of the antifreeze enters the variator system. Use only Nissan Coolant L250 (green).

Another common mistake is using sealant on rubber tube seals. This leads to clogging of the radiator channels. Instead of sealant, use new o-rings (21326-JK000).

If after replacing the radiator there is a light on the dashboard AT TEMP, check:

1. The oil level in the variator (should be between HOT And MAX on a warm engine).
2. Connecting the oil temperature sensor (located on the variator housing).
3. Integrity of electrical wiring to the radiator (breakage or corrosion of contacts).

FAQ: Frequently asked questions about the variator radiator Nissan Murano Z51

Is it possible to drive with a faulty variator radiator?

Short term (up to 500–1000 km) - yes, but with mandatory oil temperature control. If it exceeds 120°C, the variator will fail within 1–2 thousand km. At the first signs of overheating (jerking, burning smell), stop immediately and let the car cool down.

How often should the CVT radiator be replaced?

There is no routine replacement, but in practice the radiator serves:

• 150–200 thousand km - with careful operation and regular oil changes.
• 80–120 thousand km - when driving in traffic jams or with a trailer.

Check its condition every time you change the oil in the variator.

Is it possible to flush the variator radiator without removing it?

Yes, but the efficiency will be low. For washing:

1. Disconnect the radiator return pipe.
2. Connect a hose to it and pump it 2–3 l fresh oil NS-3 under pressure.
3. Repeat the procedure 2-3 times.

This method will remove ~60–70% sediments. For complete cleaning, the radiator must be removed and washed with ultrasound.

What kind of oil should I pour into the variator after replacing the radiator?

Only Nissan CVT Fluid NS-3 (article KLE52-00004). Analogs (for example, Idemitsu CVTF or Ravenol CVT) can only be used if they are approved Nissan NS-3. Volume for complete replacement: 10–12 l (depending on the method).

How much does it cost to replace a CVT radiator at a service center?

Cost of work at official dealers Nissan — 8–12 thousand rubles. In independent services - 5–7 thousand rubles. Total price with spare parts:

• Original radiator + work: 20–25 thousand rubles.
• Analogue (Denso or Koyorad) + work: 15–18 thousand rubles.