Slide 1. Introduction.
The class develops what a glow plug is in a diesel car, the symptoms and faults that can cause a vehicle to fail its MOT, and the implications for fleet management.
Slide 2. Glow plugs.
In diesel engines, the glow plug is a key component in facilitating starting, especially in cold climates. Although not visible to the naked eye, its proper functioning is essential for the car to start without problems.
In modern vehicles, there is usually a light on the instrument panel that indicates the status of the glow plugs. Sometimes, the “Check Engine” warning light may even come on, underscoring the importance of these small but important parts.
- What is the function of the glow plug?.
- Heat to facilitate ignition.
Glow plugs heat the air inside the cylinder to temperatures above 1,000°C, which helps the diesel fuel ignite when mixed with the compressed air. Their function is especially important during the first few seconds after starting, as they reduce smoke and improve efficiency.
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- Differences from gasoline spark plugs.
Unlike conventional spark plugs, which produce a spark, glow plugs function as a resistor that generates heat. Their function is quieter, but just as important.
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- Where are glow plugs located?.
They are installed inside the combustion chamber, on the outside next to the engine cylinders, although their specific location depends on the vehicle design. In some cases, it may be necessary to remove components such as the intake system or fuel lines in order to access them. It is best to consult the car manual to identify them correctly.
- Symptoms of a glow plug in poor condition.
Dirt resulting from fuel combustion is the main reason why these components stop working properly.
A faulty glow plug can cause multiple problems.
- Starting problems.
This is the main symptom of a faulty heater. Problems mainly occur when it is cold and there is high humidity. If the glow plug does not generate enough heat, the cylinder will not heat up enough for combustion to start.
- Poor acceleration.
If one of these components fails, when you press the accelerator you will notice that the car does not accelerate as it should. However, there are other engine problems that can cause this failure.
- Higher emissions.
One of the functions of heaters is to reduce emissions and smoke. If you see that the smoke is very dark or black, it may be due to a faulty spark plug.
- The Check Engine light comes on.
In vehicles that do not have a special indicator light for spark plugs, the engine check light will come on. The OBD2 scanner will return error code P0380.
- Other faults.
You may hear knocking noises or experience other faults, such as unstable engine performance when the spark plugs are not burning the fuel properly.
- How to check the condition of glow plugs.
Manual check with a multimeter.
If you have basic mechanical knowledge, you can perform a preliminary check.
- Disconnect the negative battery terminal.
Locate the spark plugs and remove them.
- Use a multimeter in continuity mode.
- If any of them do not show continuity, they must be replaced.
- The failure of a single spark plug can affect engine starting and performance.
- How often should they be changed?.
The service life varies depending on the use of the car, the condition of the engine, and the quality of the fuel. As a general reference, it is recommended to change the spark plugs every 120,000 kilometers. In cold climates or with frequent urban use, this interval may be shorter. Performing regular checkups helps avoid unpleasant surprises.
- How are spark plugs replaced?.
Changing spark plugs is a task that can be done if you have the tools and some experience.
- Disconnect the battery.
- Access the spark plugs by removing the necessary components.
- Unplug each spark plug and remove it carefully.
- Apply lubricant to the threads of the new spark plugs to facilitate installation.
- Make sure they are aligned correctly before tightening them.
- Ideally, replace all of them at the same time for uniform performance.
- Implications for fleet management.
The main consequence of a breakdown is the cost of replacing the glow plugs, failing the MOT test, and the time the vehicle is out of service.
It is recommended that vehicle maintenance be carried out according to the manufacturer's instructions, within the specified time frame, by qualified personnel and in an appropriate workshop.
If a single glow plug fails, the engine will not start, and it is recommended that all glow plugs be replaced at the same time.
Glow plugs wear out over time and when they reach a certain number of kilometers or starts, they will stop working sooner or later.
Glow plugs do not warn when they are going to stop working; they do so suddenly. You may find that the glow plug is working fine and then stops working the next time you start the engine, so it is very important to replace them when indicated by the vehicle manufacturer.
It is recommended to use official spare parts from the vehicle manufacturer or premium spare parts brands.
In summary, a damaged glow plug can cause misfiring, increased fuel consumption, high emissions, and make it difficult to pass the MOT test. In addition, forcing the engine to start without the help of these glow plugs can wear out other components.
Proper maintenance and following the manufacturer's recommendations will prevent costly breakdowns and improve the overall reliability of the vehicle.
Slide 3. Thank you for your time.
The class has developed what a glow plug is in a diesel car, the symptoms and breakdowns that can cause a vehicle to fail the MOT test, and the implications for fleet management, see you soon.
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