Car Maintenance

Reasons Why Glow Plug Warning Light is ON

Let’s delve into the reasons behind the glow plug warning light and the appropriate responses to keep your diesel engine running smoothly. The glow plug warning light, a familiar sight on the dashboard of diesel-powered vehicles, serves a crucial role in ensuring smooth starts, particularly in colder temperatures. While warning light usually signals routine heating assistance, its persistence or flashing can indicate underlying issues that demand attention.

Understanding the Glow Plug Warning Light

Normal Operation: Under standard conditions, the glow plug light activates when initiating a diesel car in cold weather. This coil-shaped symbol, resembling a double-looped coil, signifies the activation of glow plugs, providing essential heat to facilitate the ignition process. Typically, the light extinguishes within 5 to 10 seconds or as soon as the engine reaches an optimal temperature.

Warning Signal: The glow plug warning light transforms from a routine indicator to a warning when it starts flashing or persists even after the engine has ignited. This change alerts drivers to potential issues with the glow plug, its timer, or the diesel engine itself.

Reasons for Glow Plug Warning Light Activation

  1. Cold Weather:
    • Normal Operation: During winter, the glow plug light indicates the need for additional heating due to cold temperatures.
    • Warning Sign: If the light remains on for an extended period or starts blinking, it goes beyond the usual cold-weather activation.
  2. Failing Glow Plug:
    • Indicator: If the light stays on for more than 10 to 15 seconds, it suggests a decline in the glow plug’s efficiency.
    • Action Required: Prompt replacement is necessary to prevent potential engine issues.
  3. Worn-Out Glow Plug:
    • Indicator: Prolonged glow plug light activation without ignition points to a worn-out glow plug.
    • Action Required: Immediate replacement is crucial, and flashing indicates a complete loss of power.
  4. Malfunctioning Sensor-Timer:
    • Indicator: Temperature sensor-equipped timer malfunctions result in incorrect glow plug activation.
    • Action Required: Timely intervention prevents engine underheating or overheating, avoiding potential damage.

Is it Safe to Drive with the Glow Plug Warning Light On?

  • Steady Glow: If the glow plug warning light remains on without flashing after ignition, exercise caution. Wait until the light turns off before driving, as it ensures optimal engine conditions.
  • Flashing Light: A flashing glow plug warning light indicates potential starting issues, and driving may not be possible usually sometimes faulty glow plug will cause light to flash. Seek professional assistance immediately. Could also indicate diesel particular filter issue. If doesn’t loose power drive to local garage. See owners manual there can be more related description.
  • Combined with Engine Warning Light: Simultaneous activation with the engine warning light suggests overheating. Possible DPF blocked and needs regeneration. If doesn’t loose power drive to local garage immediately. See owners manual there can be more related description.

Light Color and MOT Considerations

  • Light Color: Glow plug warning lights are typically yellow or orange double looped coil symbols.
  • MOT: In normal cold conditions, the glow plug light’s activation won’t cause MOT failure. However, a flashing light or prolonged activation during the test may result in failure.

Glow Plug

Understanding the glow plug warning light’s signals empowers drivers to respond appropriately, ensuring the longevity and performance of diesel engines. Regular checks, timely replacements, and professional intervention when needed contribute to a reliable driving experience. Whether facing the chill of winter or the occasional warning light, a proactive approach to glow plug maintenance ensures that your diesel-powered vehicle is always ready to hit the road. Bugatti service schedule.

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