Diesel engines installed in SUVs Nissan Patrol, are distinguished by high power and torque, but require special attention to the cold start system. At low temperatures, it is the glow plugs that play a decisive role in starting the power plant. Without their correct operation, the engine may be unstable, smoke, or not start at all before warming up.
Owners Nissan Patrol With diesel units, they often encounter a problem when, after a long stay in cold weather, the engine starts with great difficulty, and the spiral icon lights up on the instrument panel. This is a sure sign that the combustion chamber preheating system has ceased to perform its functions. Ignoring this problem can lead to serious damage to the piston group due to detonation and incomplete combustion of fuel.
A competent approach to servicing the starting system includes not only timely replacement of elements, but also regular checking of their resistance and wiring condition. Glow plugs - this is not a consumable item that changes “according to regulations”, but a critical component that requires diagnostics at the first sign of a malfunction. In this article we will look at all the nuances of choosing, checking and installing these elements for your car.
Operating principle of the preheating system
To understand why glow plugs so important, it is necessary to consider the physics of the ignition process of diesel fuel. Unlike gasoline engines, where the mixture is ignited by a spark, in a diesel engine ignition occurs when air is compressed and reaches a critical temperature. However, when cold, the metal of the cylinder block and piston removes heat faster than the mixture can heat up.
Heating system Nissan Patrol solves this problem using electric heating elements built into the combustion chamber. When you turn the ignition key, the relay supplies voltage to glow plugs, which in a few seconds heat up to temperatures from 800 to 1000 degrees Celsius. This ensures instant ignition of the fuel-air mixture immediately after the starter begins to rotate.
It is important to note that modern systems used in Patrol with a YD25 or TD42 engine, they work not only at the start-up stage. The electronic control unit can keep the spark plugs working even after the engine is started for a certain time to stabilize idle speed and reduce noise and vibration levels.
- 🔥 Fast Heating: Modern ceramic elements reach operating temperature in less than 3 seconds.
- 🌡️ Stability of operation: maintaining optimal temperature in the combustion chamber even with a sharp drop in speed.
- 💨 Environmental friendliness: complete combustion of fuel reduces emissions of soot and toxic substances in cold mode.
Main signs of faulty glow plugs
The malfunction of one or more spark plugs can be determined by indirect signs that appear in engine operation. The most obvious symptom is difficult starting in the cold season. If before the car started with half a turn, but now you have to turn the starter for 10-15 seconds, the problem is clearly in the heating system.
Another warning sign is the appearance of black smoke from the exhaust pipe immediately after starting. This indicates incomplete combustion of the fuel, since the temperature in the cylinder with a faulty spark plug is insufficient for effective oxidation of diesel fuel. The driver may also notice unstable engine operation at idle, accompanied by vibrations.
On some models Nissan Patrol a system malfunction may be indicated by a flashing "spiral" indicator on the instrument panel. If the icon is constantly on or flashes when the ignition is on, this indicates an error in the control circuit. However, if the indicator works properly, but the engine does not start, the problem may be deeper - in the heating coil itself.
⚠️ Attention: Do not try to start the engine multiple times in a row if the glow plugs are faulty. This can lead to overheating of the starter and discharge of the battery, as well as washing off the oil film from the cylinder walls.
- ❄️ The starter cranks for a long time when trying to start in cold weather.
- 🌫️ Increased smoke from the exhaust pipe in the first minutes of operation.
- ⚙️ Uneven engine operation, misfires in individual cylinders.
- 🔋 Rapid battery discharge due to long-term starter operation.
Diagnostics and performance check
Before you go to the store for new parts, you need to make sure of the malfunction. Diagnostics glow plugs on Nissan Patrol carried out using a multimeter and requires access to spark plugs, which may be hidden under the intake manifold or other components. The process begins with a visual inspection of the contacts and the condition of the wires.
The main test method is to measure the resistance of the heating element. To do this, you need to disconnect the power connector, set the multimeter to resistance measurement mode and touch the probes to the central contact of the spark plug and its body (ground). Normal resistance for most models ranges from 0.5 to 2.0 ohms.
If the device shows infinite resistance (break), it means that the spiral has burned out and the element must be replaced. If the resistance is too low (close to zero), there is likely a short circuit inside the element. It is also important to check the integrity of the insulator, as cracks can lead to a breakdown on the engine housing.
Additionally, it is worth checking the voltage supplied to the spark plugs. To do this, connect a multimeter to the connector and ask an assistant to turn on the ignition. The voltage must correspond to the nominal value of the on-board network (about 12-14 volts). If there is voltage but no heating, the spark plug itself is to blame. If there is no voltage, the problem is in the relay, fuse or wiring.
- Every 50,000 km
- Every 100,000 km
- Only in case of breakdown
- Never changed
☑️ Checking the system before replacement
Selection of original and analog spare parts
When selecting spare parts for Nissan Patrol It is important to take into account the specifics of the engine. Older models with the TD42 engine often use simple metal spark plugs, while modern YD25 diesels require high-temperature ceramic elements. Using the wrong type may result in overheating or mechanical damage to the combustion chamber.
Original spare parts Nissan (series references 22448) guarantee a perfect fit in size and performance. They undergo strict quality control and are designed to last a long time in the extreme operating conditions of an SUV. However, their cost can be significantly higher than their analogues.
There are many high-quality analogues on the market from trusted brands, such as Bosch, Denso, NGK or Calorstat. These manufacturers are often suppliers to the assembly lines of automakers, so their products are not inferior in quality to the original, but are cheaper. The main thing is to make sure that the analogue meets the technical requirements of your engine.
Please read part numbers and specifications carefully. An error in thread length or diameter can result in the spark plug not screwing in or protruding into the combustion chamber, which can cause piston impacts and engine damage. Glow plugs - this is not an element that you should save on by choosing the cheapest options without a brand.
| Manufacturer | Item type | Approximate resource (km) | Features |
|---|---|---|---|
| Nissan (OEM) | Ceramic/Metal | 100 000+ | Ideal geometry, high reliability |
| Bosch | Ceramic | 80 000 - 120 000 | Fast heating, excellent corrosion protection |
| Denso | Ceramic | 90 000 - 110 000 | High stability of characteristics at low temperatures |
| NGK | Ceramic | 80 000 - 100 000 | Excellent value for money |
Glow plug replacement process
Replacement glow plugs on Nissan Patrol - a task of medium complexity that requires accuracy and the right tools. Before starting work, be sure to let the engine cool completely, as working with hot parts can lead to burns, as well as the risk of stripping threads due to thermal expansion of the metal.
First you need to remove the decorative engine covers and disconnect the electrical connectors from the spark plugs. Often the wires stick or oxidize, so they need to be gently rocked so as not to break. Use a special glow plug wrench that has a magnetic holder or rubber insert to hold the element inside the sleeve.
Unscrew the spark plugs slowly and evenly. If the element is stuck, do not use excessive force as this may cause the spark plug inside the cylinder head to break. In this case, a complex procedure for removing the residue will be required, which will significantly complicate the repair. Use a penetrating lubricant (WD-40 or equivalent) if the threads are stuck.