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Glow Plug Warning Light: What does Glow Plug Light Mean?


Glow Plug Warning Light: In diesel engines, the air fuel mixture is burned by injecting fuel over the compressed and heated air, not through plugs. When the diesel is sprayed on to the compressed air in the combustion chamber, the hot air must have a temperature of 700-900 ° C.

However, since the combustion chamber is cold during the first start of the engine, the temperature of the compressed the air does not reach the temperature at which it will burn the diesel that is sprayed.

Therefore, in diesel engines, the combustion chamber needs to be heated during the initial operation.

Before the engine starts, it is called a glow plugs for heating the combustion chamber.

The glow plugs (pre-heating plugs) are electrically actuated resistors that look at the tip of the rod probe in the combustion chamber.

Glow plug; makes the engine easier to operate by heating the combustion chamber, which is cold during the first ignition of the vehicle.

Glow Plug Life Span

The glow plugs have an average life of 100,000 km. However, this will change slightly depending on how to start  your car. For example: if you have a habit of starting the vehicle without waiting the all lights goes off, you will reduce the using of glow plug’s life.

How Do I Know If I Have a Glow Plug Failure?

  • If the glow plug warning light is ON,
  • If your car is not working at the first time,
  • If your car starts easily in summer and your car cannot start easily in winter,

the glow plug is defective.”

If the glow plug is broken, you should take your vehicle to a service as soon as possible to replace the damaged glow plugs.

Why Does the Glow Plug Fail?

  • Press the starter without going off the lights of glow plug,
  • Leaving open the ignition switch for a long time,
  • Press the starter with weak battery for a long time,

It causes the glow plug to break down early.

The operating time of the glow plug may increase or decrease depending on the temperature of the engine and air. The engine should not be started until the warning light goes out. Pressing the starter for a long time can give damage to your plugs.

Why Does Diesel Heater Plug Warning Light Turn On?

  • There may be a problem with the incoming current voltage to the heater plug.
  • Continuous electric current in heater plug. (It will cause the burning)
  • There ought not to electric current in heater plug. (Should be checked with voltage meters.)
  • Heater Plug may be burnt. (For this reason, the light of heater plug always ON)

Where is the Glow Plug Location in the Car’s Engine?

The glow plugs are mounted inside the cylinder head. The glow bar extends into the glow chamber or into the front chambers. However, the glow bar must be positioned at the exact edge of the fuel mixture. This way heat can be generated where it is needed exactly.

Hüseyin Aksoy is an automotive expert with more than 10 years of industry experience.

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Comments (1)

  1. September 21, 2023

    My Ford engine goes off immediately the heater plug light comes on,then I have to start the engine again,what could be responsible for this,thanks

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