Engine cooling system on a crossover Nissan Murano the second generation (Z51 body) is one of the critical components to ensure the long life of the VQ35DE or VQ35HR engine. It is the thermostat that regulates the flow of coolant, causing the engine to warm up to operating temperature faster and preventing it from overheating in the summer heat or under high loads. Failure of this small but important component can lead to serious consequences, including deformation of the cylinder head.
Owners Nissan Murano Z51 Often we are faced with the fact that the car begins to behave unpredictably: the temperature gauge drops when driving along the highway or, conversely, rises in traffic jams. These symptoms are often ignored until the overheating light comes on or your fuel consumption increases. Understanding of operating principles thermostat will help you diagnose the problem in time and avoid costly engine repairs.
Operating principle and unit design
Main task thermostat consists of regulating the flow of antifreeze between the small and large cooling circles. When cold, the valve is closed and the fluid circulates only in a small circle, allowing the engine VQ35 quickly reach operating temperature of about 90 degrees Celsius. As soon as the temperature reaches the response threshold, the wax tablet inside the valve expands and opens the damper.
After opening the valve, coolant begins to flow into radiatorwhere intense heat exchange with the surrounding air occurs. If the thermostat is stuck in the open position, the engine will take a long time to warm up, especially in winter, which leads to increased fuel consumption and wear of parts due to operation in “cold” friction mode. When stuck in the closed position, there is a risk of critical overheating, which can destroy the head gasket in a matter of minutes.
By car Nissan Murano Z51 A wax-filled thermostat is used, which is sensitive to the quality of the coolant. Using low-quality antifreeze or mixing different types of fluids can lead to the formation of deposits that interfere with the operation of the mechanism. Regular condition check coolant - the key to proper operation of the thermostat.
Main symptoms of a malfunction
Determine if the thermostat is broken Nissan Murano Z51 can be determined by a number of characteristic symptoms that manifest themselves in the behavior of the car. The most obvious sign is the unstable operation of the temperature gauge on the dashboard. If the arrow jumps or shows low values when driving along the highway, it means that the valve does not close the large circle.
- 🌡️ The engine does not reach operating temperature (below 80°C) when driving at a speed of more than 60 km/h.
- 🔥 A sharp jump in temperature to the red zone after a short trip in the city cycle.
- 🌫️ Difficulty starting the engine in the cold season due to long-term operation on an unheated engine.
In addition to temperature indicators, indirect signs, such as increased fuel consumption, may also indicate a malfunction. The electronic control unit (ECU) tries to compensate for the low temperature by enriching the mixture, which leads to excessive consumption of gasoline. It is also worth paying attention to the operation of the cabin heater: if the air flow becomes cold even when the engine is warm, this is a sure sign that thermostat valve stuck open.
In some cases, the malfunction is accompanied by strange sounds under the hood or coolant leaks. Over time, the thermostat O-ring loses its elasticity and begins to leak antifreeze. If you notice wet marks in the area of the thermostat or a specific sweetish smell in the cabin, you need to urgently carry out diagnostics.
Selection of original spare parts and analogues
When choosing thermostat for Nissan Murano Z51 It is important to understand the difference between the original part and high-quality analogues. The original from Nissan (part number 21010-1LA0A or its modification) is distinguished by high operating accuracy and durability, but is much more expensive. Many owners note that original products last more than 100 thousand kilometers without problems.
There are reliable analogues on the market from brands such as Hella, Mapco or Gates. These manufacturers offer products that often surpass the original in the quality of case materials, but may have nuances in opening temperature. Before purchasing, be sure to check the appropriate operating temperature (usually 82°C or 85°C) so as not to upset the calibration of the engine.
You should avoid cheap Chinese fakes, which often cannot withstand the pressure in the cooling system and begin to leak after just a couple of months. Saving on such an important detail as thermostat, may result in the need to replace the cylinder head gasket, which will require complex and expensive repairs.
- Original Nissan
- High-quality analogue (Hella/Gates)
- Cheap analogue
- Haven't changed it yet
Tools and preparation for replacement
Replacing the thermostat with Nissan Murano Z51 - a procedure of medium complexity that can be performed independently if you have a basic set of tools. You will need a 10mm wrench to drain the antifreeze, a set of sockets, a Phillips screwdriver and a container to drain the liquid. Don't forget to buy a new one thermostat and fresh coolant, since it is recommended to completely drain the old one when replacing it.
☑️ Preparing to replace the thermostat
It is best to carry out work on a cooled engine to avoid burns from steam and hot liquid. Open the hood and locate the upper radiator hose that goes to the thermostat. On some trim levels, access to the unit may require removing the decorative engine cover and air filter. Carefully unscrew the clamps and remove the pipes, placing a container for drainage.
After removing the pipes, unscrew the bolts securing the thermostat housing. Be extremely careful not to damage adjacent surfaces. Clean the installation area from old gasket residues and dirt using solvent and a soft cloth. Improper cleaning can cause leaks even with a new seal.
The nuances of removing the pipe from the thermostat
Connection to Nissan Murano often sticks to the body. Do not try to jerk it sharply, as this may break the plastic thermostat housing. Use WD-40 or penetrating lubricant, let it sit for 10-15 minutes, and then gently wiggle the pipe, gradually removing it from the seat.
Step-by-step replacement instructions
Installing a new thermostat starts with checking the quality of the O-ring. Make sure it fits snugly in the housing and is free of defects. Insert the new valve into the body, ensuring the correct orientation. Some models have a mark or protrusion that should line up with the corresponding slot in the engine.
Tighten the thermostat housing bolts to the torque recommended by the manufacturer (usually about 10-12 Nm). Tightening too tightly can lead to a crack in the housing, and tightening too weakly can lead to leakage. After installation, return the pipes to their place and secure them with new clamps. It is better to replace old clamps, as they may not provide sufficient clamping.
Fill the expansion tank with new coolant up to the MAX mark. Start the engine and let it idle. Watch the thermostat open: the lower radiator hose should become hot. If this does not happen, there may be an air lock left in the system.
- 🛠️ Use a torque wrench to tighten the thermostat housing bolts.
- 💧 Check the antifreeze level while the engine is warming up.
- 🚗 After replacement, take a short trip to check the system's operation under load.
If you notice that the fluid level has dropped, top it up to normal. It is important to remove all air pockets from the system, as they can interfere with circulation and lead to local overheating. Warm up the engine until the radiator fan turns on and make sure that the temperature remains stable.
When replacing the thermostat, it is recommended to immediately replace the expansion tank if it has microcracks or has become cloudy over time, since the plastic loses its properties and can burst under pressure.
Common mistakes and expert advice
Many owners Nissan Murano Z51 They make the mistake of trying to “bleed” the cooling system by simply opening the reservoir cap. This is ineffective and dangerous. To remove air efficiently, it is necessary to raise the front of the car on a lift or jacks so that the expansion tank becomes the highest point of the system.
Another common problem is the use of low-quality antifreeze. Cheap fluids can corrode metal parts and destroy rubber seals. Use only those specified for Nissan fluids such as Nissan Long Life Antifreeze/Coolant Blue or their high-quality analogues.
⚠️ Attention: Never open the expansion tank cap on a hot engine! The pressure in the system can be critical, which will lead to the release of boiling water and severe burns to the face and hands. Wait until the motor cools down completely.
It is also worth paying attention to the condition of the coolant temperature sensor. If the thermostat is working properly, but the temperature readings on the instrument panel do not correspond to reality, the problem may be in the sensor, and not in the mechanical part of the unit.
Proper bleeding of the cooling system Nissan Murano Z51 requires the front of the car to be raised so that the expansion tank becomes the highest point for air to escape.
| Parameter | Meaning | Note |
|---|---|---|
| Opening temperature | 82-85 °C | Depends on engine modification |
| Coolant type | Nissan Long Life Blue | Or G12/G13 equivalent |
| Housing material | Plastic/Metal | The original often has a metal body |
| Part resource | 100,000+ km | Provided you use high-quality antifreeze |
Sometimes owners are faced with the fact that after replacing the thermostat the problem does not go away. In this case, it is worth checking the operation of the radiator fans and the condition of the water pump. If the pump does not create enough pressure, fluid circulation will be disrupted and the engine will overheat even with a working thermostat.
⚠️ Attention: If the engine continues to overheat after replacing the thermostat, immediately stop driving the vehicle and check the operation of the water pump and fans, as the problem may be their failure.
Questions and answers
How often should I change the thermostat on a Nissan Murano Z51?
The recommended replacement interval is 100,000 kilometers or every 5-6 years, whichever comes first. However, if low-quality antifreeze is used, the service life can be reduced to 50,000 km.
Is it possible to drive with a faulty thermostat?
It is possible for a short time, but not recommended. If the thermostat is stuck open, the engine will run cold and will increase fuel consumption and emissions. If it is closed, there is a high risk of overheating and major engine repairs.
Do I need to flush the cooling system when replacing the thermostat?
If you are replacing a thermostat due to mechanical failure, flushing is not necessary. If the problem was contamination or corrosion, then a complete flushing of the system with distilled water or a special liquid is mandatory.
What is the original thermostat number for Murano Z51?
The most common original part numbers are: 21010-1LA0A, 21010-EA000. Before purchasing, be sure to check the VIN number of your car, as there may be nuances depending on the year of manufacture and engine type.
What to do if the new thermostat is leaking?
Perhaps the seating surfaces were not cleaned properly or the sealing ring was skewed during installation. Try tightening the fastening bolts, but if the leak is not eliminated, you will have to remove the assembly and check the integrity of the gasket and surface for cracks.