Glow Plug: Testing and Inspection

The following examples of glow plug failures give different clues to cause of failure:

There is no visible damage, but glow plug is electrically open. This indicates an internal heating element failure.

Glow plug tip that is missing can be caused by incorrect timing or poor fuel quality.

Multiple, distorted glow plugs are usually caused by electrical overheating. A complete inspection of the glow plug control system should be made.