Glow Plug Warning Light: What Does It Indicate in a Diesel Car?

Glow plugs or heaters are responsible for facilitating the correct operation of a diesel engine by preheating the combustion chamber. Because of the way a diesel engine is designed, there are times when they require some help to start.

For this, they need yes or yes some heaters. Now, like any other part of a vehicle, this one also suffers from wear, it can be defective or break down, and we will know this with the help of the glow plug warning light .

A vehicle's instrument panel is equipped with many symbols that allow drivers to know the status of different parts and systems.

This also includes a warning light in the shape of the coil or spring, that of the heaters. There are a few different reasons why this warning light may come on and indicate a malfunction of this mechanical component. Read on to find out how it affects you as a driver.

What are diesel heaters?

A heater is an essential component for a diesel engine to start. These are crucial especially in colder environments , since diesel has a higher density than gasoline and freezes at a lower temperature (at -34ºC; at -20ºC it crystallizes and at -10ºC it thickens).

Diesel engines rely on the heat created by compression in the chamber to start properly. When it lacks an external heat source and at the same time is exposed to extremely cold weather, a diesel engine will not be able to start.

The solutions to this problem are glow plugs or heaters. But, with what we have just said, it does not mean that in summer they are not useful. We have already said it at the beginning: a heater is an essential component for a diesel engine to work. This part is a heating element that activates during cranking when the engine temperature is low . That is why the engine takes a little longer to start after spending the night in the open than after having stopped to eat at a transit bar, for example.

A heater increases the temperature inside the cylinders to facilitate pressurization and detonation of the diesel fuel. The system normally makes the driver wait about 10 seconds while the glow plugs heat up the engine (time the glow plug warning light stays on on the instrument panel). Once the correct temperature has been reached, the car will let you know with the disappearance of the warning light.

How do diesel heaters work?

In addition to oxygen and fuel, a booster also requires an ignition point to function . The glow plugs provide ignition by heating the small coil inside the equivalent of the spark plug, with the help of a 1.5V battery that sits on the edge of the glow plug. This battery can sometimes be found mounted on board in certain newer vehicles.

The type of diesel and the material of the element itself will determine how hot the heater will stay after the engine has successfully started. The fuel, which has methanol in it, will come into contact with the element, which is made of several different alloyed metals, and the contact between the two will create a catalytic reaction . This reaction heats the platinum while causing the methanol to ignite.

What does the heater warning light tell me?

Normally the glow plug warning light will come on only when the engine is cold. If this light is flashing , there is a problem . The most common reason for replacing glow plugs is age (around 100,000 km).

Over time and after many cycles, a heater ages and cannot generate the necessary heat. Replacing any malfunctioning heaters should eliminate any problems you have. Now, why?

If the glow plug warning light flashes, it is possible that the car's engine management unit (ECU) has detected an error that may be related to one of the glow plugs, the control module of the aforementioned or even a sensor that is not directly connected to the glow plug. necessarily related to it. Once the ECU detects a possible heater malfunction, it will record diagnostic data that a qualified mechanic will then use on their code reader to interpret it and figure out the problem.

When the glow plug symbol becomes visible on the car, your fellow driver is likely going into a "safe mode" (if he's relatively modern) to prevent any damage to the engine. When in this setting, you may notice that your journal mount will experience a dramatic drop in performance. Depending on the severity of the problem, it may be safe to drive the vehicle extremely short distances until the problem can be properly diagnosed and repaired, but don't let it go.

It can be extremely stressful to deal with the glow plug light flashing, and it can be equally annoying if the light doesn't come on at all . Both of these are warning signs of a malfunction inside the car that can cause you unwelcome damage like a completely disabled engine. That's why it's crucial to have your vehicle professionally diagnosed right away if you're presented with either of these two alternatives. Avoid driving as much as possible and never assume "it can wait" .

Is it safe to drive with the heater warning light on?

Some engines can't even start until the warning light goes out, which prevents drivers from starting the engine too soon. We must always wait for the warning light to go out before trying to start .

Having some patience will help you keep the engine running in the long run. And if it starts to blink in circulation, which we have just mentioned a few lines above: the car will enter a "safe mode" and the engine performance will drop precipitously. That is indicative of going to the workshop directly.