<em>Nissan Murano Z50</em>variator thermostat: signs of malfunction and replacement instructions

Nissan Murano Z50 - crossover with CVT JF016E, which is sensitive to overheating. The variator thermostat in this model plays a key role in maintaining optimal oil temperature, but often fails after 100–150 thousand kilometers. If you ignore the symptoms of a malfunction, the consequences can cost 200–300 thousand rubles to repair the variator.

In this article we will look at how the variator thermostat works. Murano Z50, what signs to use to diagnose it, what original and similar spare parts are suitable, and we will also give step-by-step replacement instructions with nuances for engines VQ35DE And VQ25DE. We will pay special attention to typical repair mistakes that lead to repeated overheating.

Functions of the variator thermostat and operating principle

Thermostat in the variator Nissan Murano Z50 - This is not just a valve, but part of the cooling system that regulates the flow of oil through the radiator. Its main task is to speed up the warm-up of the variator in cold weather and prevent overheating under load. Unlike the engine thermostat, it works with oil, not antifreeze, and has a different temperature range.

Working principle:

• 🔹 During a cold start, the thermostat closed — the oil circulates in a small circle (bypassing the radiator) in order to quickly heat up to operating temperature (60–80°C).
• 🔹 Upon reaching 85–90°C the valve begins to open, sending oil through the radiator for cooling.
• 🔹 When overheating (over 100°C), the thermostat opens completely, forcing cooling.

On Murano Z50 The thermostat is integrated into the variator oil pump housing, which makes it difficult to replace. In models with VQ35DE (3.5 l) it fails more often due to greater load than in VQ25DE (2.5 l).

Signs of a malfunctioning CVT thermostat

The main problem is the thermostat sticks in closed or open position. In the first case, the variator overheats, in the second it takes a long time to warm up, which impairs the smoothness of switching. Let's look at the key symptoms:

• ⚠️ Jerks during acceleration after warming up, the oil does not cool down and loses viscosity.
• ⚠️ Long warm-up of the variator (more than 10–15 minutes) even in warm weather.
• ⚠️ Check Engine with errors P1778 (variator overheating) or P0715 (faulty oil temperature sensor).
• ⚠️ Hum or vibration when driving - the oil is too thick due to the low temperature.

The most reliable diagnostic method is to measure the temperature of the variator oil using a scanner (for example, Launch X431 or ELM327). Normal indicators:

Operating mode	Oil temperature, °C
Cold start	20–40
City mode	70–90
Driving on the highway	80–95
Critical overheating	Over 110

If the temperature does not rise above 60°C or exceeds 100°C, the thermostat is faulty. On a Murano Z50 with a mileage of more than 120 thousand km, it is recommended to change the thermostat preventively, even if there are no obvious symptoms.

Original articles and analogues of the thermostat

For Nissan Murano Z50 (2007–2014) the following thermostats are suitable:

• 🔧 Original: 31726-JK00A (for variator JF016E) — price ~5,000–7,000 RUR.
• 🔧 Analogues:
• 🔹 ATP TB-338 (~3,500 ₽) is a popular choice, but there are cases of defects.
• 🔹 Nipparts J31-726-000 (~4,200 ₽) - a high-quality Japanese analogue.
• 🔹 Denso 553-0105 (~4,800 ₽) - reliability at the level of the original.

When purchasing, check compatibility with your year and engine type. For example, a thermostat for Murano Z51 (2015+) will not work! Also pay attention to the package: some kits come with a gasket 31728-JK00A (price ~800 ₽), in others you need to buy it separately.

⚠️ Attention: There are many fake brands on the market Nissan. The original thermostat has a laser engraving of the article number and a hologram on the packaging. Check with authorized dealers or stores with a guarantee.

Step-by-step instructions for replacing the thermostat

Replacing the thermostat with Murano Z50 requires removal of the variator pan, so you can’t do without a pit or a lift. If you have little experience, it is better to contact a service center - errors during assembly can lead to oil leaks or damage to the variator.

Required tools:

Work order:

1. Drain the oil from the variator through the plug in the pan. To completely drain it, you will need to remove the radiator pipe (another ~1 liter will leak out).

2. Remove the variator pan by unscrewing 18 bolts (tightening torque during assembly - 10 Nm). Be careful: ~0.5 liters of oil remains in the pan!

3. Disconnect the oil temperature sensor connector (located next to the thermostat).

4. Unscrew the 3 thermostat mounting bolts (torque 8–10 Nm) and carefully remove it. There is a gasket under it - be sure to replace it!

5. Install the new thermostat with the gasket, observing the tightening torque. Check that the valve is in the closed position (you can blow it with air).

6. Reassemble everything in reverse order. Fill in new oil (volume - 8–9 liters for a complete change).

After replacement, be sure to reset the variator adaptations via the diagnostic scanner (for example, Nissan Consult III or Launch X431). To do this:

Выберите модель → Трансмиссия → Инициализация датчиков → Сброс адаптаций

What happens if you don't reset the adaptations?

Without a reset, the electronic control unit (ECU) will use old data from the CVT, which will lead to jerking, shift delays and accelerated belt wear.

Typical replacement mistakes and how to avoid them

Even experienced craftsmen sometimes make mistakes that ruin all the work. Here are the most common:

• 🚨 Using an old gasket - leads to oil leakage after 1–2 thousand km.
• 🚨 Incorrect tightening torque of pan bolts (too weak - leak, too strong - deformation).
• 🚨 Changing the oil without flushing the radiator - if wear products remain in the system, they will clog the new thermostat.
• 🚨 Using non-original oil (For example, Mobil CVT instead of Nissan NS-2/NS-3) - accelerates wear of the variator.

Another critical error - failure to check oil temperature sensor. If he is lying, then even a working thermostat will not work correctly. You can check the sensor with a multimeter:

Temperature, °C	Resistance, kOhm
20	2.2–2.7
60	0.6–0.8
100	0.17–0.23

⚠️ Attention: If the CVT continues to overheat after replacing the thermostat, check the oil cooler. On Murano Z50 it often gets clogged after 150 thousand km. Flushing the radiator with a special liquid (for example, LIQUI MOLY Kuhler-Reiniger) may solve the problem.

Cost of service work vs independent replacement

Prices for replacing the variator thermostat in services vary greatly depending on the region and level of the service station. In Moscow and St. Petersburg, work will cost 8,000–12,000 rubles, in the regions - 5,000–8,000 rubles. Full price:

Service	Cost, ₽
Replacing the thermostat (without oil)	5 000–8 000
Complete oil change in the variator	3 000–5 000
CVT diagnostics (scanner)	1 500–2 500
Flushing the oil cooling radiator	2 000–3 500

When replacing yourself, the main costs are spare parts and oil:

• 💰 Thermostat (original) - 5,000–7,000 ₽.
• 💰 Pallet gasket - 800–1,200 ₽.
• 💰 Oil Nissan CVT Fluid NS-3 (9 l) - 6,000–8,000 ₽.
• 💰 Variator filter (optional) — 1,500–2,000 ₽.

Total: independent replacement will cost 12,000–18,000 rubles versus 20,000–25,000 rubles in the service. However, without experience, the risk of mistakes is high - for example, incorrectly tightening the pan bolts can lead to leaks and repeated repairs.

Preventing thermostat malfunctions

The service life of the variator thermostat is Murano Z50 depends not only on mileage, but also on operating conditions. To extend its life:

• 🔧 Change the oil in the variator every 60 thousand km (and not 90-100 thousand, as recommended Nissan). Use only NS-2 or NS-3.
• 🔧 Avoid sudden starts and towing - this increases the load on the variator and oil.
• 🔧 Check the oil level every 10 thousand km. At a low level, the risk of overheating increases by 2–3 times.
• 🔧 Keep the radiator clean. Clogged honeycombs impair heat transfer, which leads to overheating.

It is also useful to carry out once a year (in spring) CVT diagnostics through a scanner. Pay attention to the following parameters:

• 📊 Real-time oil temperature.
• 📊 Pressure in the lines (should be 4-6 bar at idle and 8-10 bar under load).
• 📊 Sensor status (errors P0715, P0720 indicate problems).

If you frequently drive in traffic or in hot climates, consider installing additional variator cooling radiator. This will reduce the load on the thermostat and increase the life of the variator by 30–40%.

FAQ: Frequently asked questions about the CVT thermostat Nissan Murano Z50

Is it possible to drive with a faulty thermostat?

Short term - yes, but not worth the risk. If the thermostat is stuck in closed position, the variator will overheat within 10–15 minutes of intense driving, which will lead to damage to the belt and cones. If in open — the oil will not warm up, which will worsen the smoothness of the engine and increase wear.

Which thermostat is better - original or analogue?

Original (31726-JK00A) more reliable, but more expensive. Among analogues, they have proven themselves well Denso And Nipparts. Cheap Chinese thermostats (for example, Febi or Meyle) often jams after 20–30 thousand km.

Do I need to change the oil in the variator when replacing the thermostat?

Definitely! Old oil contains wear debris that can damage the new thermostat. Optimally, a complete replacement with washing (using the “draining” method).

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

Yes, but the efficiency will be lower. To wash without removing, use special liquids (for example, LIQUI MOLY CVT Additive). Complete cleaning requires dismantling the radiator and blowing it with compressed air.

What errors does the variator give if there are problems with the thermostat?

Most often appear:

• P1778 — overheating of the variator;
• P0715 — malfunction of the oil temperature sensor;
• P0776 — problem with pressure in the solenoid;
• P0841 — pressure discrepancy in the lines.

If these errors occur, first check the thermostat and oil level.