The crankcase ventilation system is one of the most critical components in the engine Nissan Murano Z51, especially for VQ35DE series units. Many owners are faced with an increase in idle speed or the appearance of oil mist in the pipes, without understanding the root cause. Often the problem lies in jamming or clogging PCV valve (Positive Crankcase Ventilation).
Ignoring the malfunction of this part can lead to more serious consequences, such as burnout of the crankshaft seals or oil getting into the intake system. In this article we will examine in detail how the mechanism works on Nissan Murano first generation, what symptoms indicate a breakdown and how to correctly diagnose and replace it yourself.
How the crankcase ventilation system works on the Murano Z51
In engines VQ35DE, installed on Nissan Murano Z51, the PCV system is designed to remove gases that escape from the combustion chamber into the crankcase. These gases mix with oil vapor and must be returned to the intake manifold to be burned. The process is controlled PCV valve, which opens and closes depending on the vacuum in the intake manifold.
When the engine is idling, the vacuum is at its maximum and the valve is slightly open to ensure proper circulation. At high loads, when the vacuum drops, the valve closes or changes its position to prevent the backflow of gases. Violation of this cyclicity leads to the fact that the pressure in the crankcase increases, creating a load on sealing elements engine.
Design Feature Nissan Murano Z51 is that the valve is often integrated into the oil filter housing or is located in a hard-to-reach location, making it difficult to quickly check. Correct operation of the system directly affects fuel economy and oil purity.
⚠️ Caution: If the PCV valve is completely stuck open, the engine will run rich, resulting in increased fuel consumption and soot fouling of the spark plugs.
Main Symptoms of Valve Failure
Understand that PCV valve on your Nissan Murano Z51 requires attention, based on a number of characteristic signs. The most obvious symptom is unstable engine idling. You may notice that the tachometer needle is floating, and the speed spontaneously increases to 1000-1200 rpm.
Another sure sign is the appearance of oil smudges. Due to excess pressure in the crankcase, oil begins to be squeezed out through the weakest points. Most often this occurs through the crankshaft oil seal or valve cover gasket. You may also notice an oil deposit inside air filter or on the walls of the intercooler pipes.
In addition, a faulty ventilation system may cause the error to appear. P0507 (Idle Control System RPM Higher Than Expected) or P0171 (System Too Lean). If you notice a hissing sound coming from under the hood when the engine is running, this may indicate that air is being sucked in through pressure leaks.
- 🔍 Unstable idle with floating speed.
- 🛢️ The appearance of oil stains under the car or on the engine.
- 💨 A hissing sound indicating system depressurization.
- ⚙️ Check Engine light comes on with error codes for mixture or speed.
⚠️ Attention: Do not try to turn off the engine forcibly if the speed increases sharply, this may damage the gearbox. Try first switching the selector to parking mode and pressing the brake pedal.
- Floating speed
- Oil in pipes
- Check Engine Error
- Noise under the hood
Diagnosis of PCV valve condition
Before you run to the store for spare parts, you need to verify the malfunction PCV valve. The simplest method is physical testing. Locate the valve in the engine compartment Nissan Murano Z51. It is usually located on the valve cover or connected to it with a hose.
Remove the valve and try shaking it. If you hear a characteristic clicking sound, this means that the inner rod is moving freely and the mechanism is most likely working. If the valve does not make sounds and seems solid, it means that it is jammed or completely clogged with deposits.
You can also check the operation of the system by removing the oil filler cap with the engine running. If there is a strong flow of gases and oil from the hole, and the cover is difficult to remove due to vacuum or pressure, this indicates problems with ventilation. However, on Nissan Murano This method should be used with caution so as not to stain your hands with oil.
Is it possible to clean the PCV valve?
In some cases, the valve can be repaired. Try pouring aerosol carburetor cleaner inside, letting it sit for 15-20 minutes and shaking. If the valve begins to click, you can try to install it back. But if it is old, it is better to replace it, as cleaning may be a temporary measure.
Process of replacing PCV valve on Murano Z51
Replacement PCV valve on Nissan Murano Z51 - a task of medium complexity. First, you need to de-energize the car by disconnecting the negative terminal of the battery. This is a standard safety precaution for any work on electrical equipment and engines.
Next you need to get to the valve. On VQ35DE engines it is often located under or near the intake manifold, requiring removal of some hoses and pipes. Be aware that old pipes can be fragile, so be careful not to break them.
Unscrew the old valve, clean the seat from dirt and carbon deposits. Install new original valve, making sure that the rubber o-ring is seated evenly. After this, reassemble all hoses and tubes in reverse order. Do not over-tighten the fasteners to avoid stripping the threads.
☑️ Preparing to replace the PCV valve
It is important to use only high-quality components. Cheap analogues may not provide proper discharge, which will lead to repeated breakdowns in the near future. Original parts Nissan guarantee precise pressure adjustment.
- 🔧 Use a set of socket wrenches and screwdrivers for dismantling.
- 🧼 Be sure to clean the seat before installing a new part.
- 🔩 Check the condition of the rubber hoses, replace them if necessary.
Comparison of original and analog spare parts
When choosing PCV valve for Nissan Murano Z51 There are several options worth considering. Original part from Nissan has a catalog number that guarantees compliance with factory specifications. This is the best choice if you want to be sure of durability.
However, there are also high-quality analogues from trusted brands, such as Hella, Bosch or Denso. They are often cheaper than the original and can offer similar performance. The main thing is to avoid unnamed Chinese copies, which may not fit correctly or have the wrong spring inside.
| Part type | Benefits | Disadvantages |
|---|---|---|
| Original (Nissan) | Perfect compatibility, long service life | High price |
| High-quality analogue | Average price, good quality | Requires compatibility check |
| Budget analogue | Low price | Low reliability, risk of rapid breakdown |
| Refurbished | Savings | An unpredictable resource |
Sometimes owners try to find universal valves, but this is risky. Ventilation system Nissan Murano is designed for a specific pressure, and a discrepancy between the parameters can disrupt the operation of the entire engine. Using the wrong valve can result in oil entering the engine and damaging the turbo or catalytic converter.
Before purchasing a spare part, be sure to remove the old valve and visually compare it with the new one. Pay attention to the length of the rod and the shape of the O-ring.
Impact of the malfunction on other vehicle systems
Don't underestimate the influence PCV valve on general condition Nissan Murano Z51. A faulty crankcase ventilation system creates excess pressure that affects seals and gaskets. Over time, this leads to their destruction and the appearance of oil leaks.
Additionally, if the valve is stuck in the closed position, gases cannot escape from the crankcase. This may cause the crankshaft seal or valve cover to rupture. Oil can get into the cooling system or intake tract, causing serious damage. The intake manifold may become filled with oil, causing water hammer or detonation.
It is also worth considering the impact on environmental friendliness. The PCV system plays an important role in reducing emissions. If it does not work, the car may not pass inspection due to exceeding toxicity standards. Regularly checking this part will help avoid such problems.
Timely replacement of the PCV valve prevents destruction of engine seals and protects the intake system from oil contamination, extending the life of the vehicle.
Frequently asked questions from Nissan Murano Z51 owners
How often should I replace the PCV valve on a Nissan Murano Z51?
Officially, the manufacturer does not indicate the exact replacement interval for Nissan Murano Z51, but experts recommend checking the condition of the valve every 60,000 kilometers. If symptoms of malfunction appear, replacement should be carried out immediately.
Is it possible to drive with a faulty PCV valve?
You can drive for a short time, but it is dangerous. Increased pressure in the crankcase can lead to seal failure and oil leakage. In the long term, this can lead to costly engine repairs.
How much does it cost to replace a PCV valve at a service center?
The cost of work depends on the region and service. On average, replacing a valve along with spare parts will cost from 3,000 to 6,000 rubles. If removal of the intake manifold is required, the price may be higher.
Why does oil accumulate in the pipes?
Oil accumulates in the pipes due to the operation of the crankcase ventilation system, which returns oil vapors back to the intake. However, excess oil indicates a faulty PCV valve or a clogged oil filter.
Regular diagnostics of the crankcase ventilation system will help to avoid serious engine damage and preserve its resource for many years.