Glow plug: common defects and their signs

1. Carbon deposit formation
   • Troubled engine start is possible.
   • Glow plug warning light can be active on the dashboard.
   • Gray smoke from the exhaust pipe is noticeable at cold engine start.
2. Deformation or damage of the tip
   • The power unit doesn’t start on the first try during cold season.
   • The engine work is unstable at start.
   • The engine doesn’t start in some cases.

How to replace glow plug?

Averagely glow plug service life is 60 000 - 80 000 operational kilometers and it depends on vehicle operation conditions and car fuel system condition. Unserviceable component is not subject to repair so it is replaced. Even if only one glow plug is faulty, specialists recommend to replace the whole set.

DIY diagnostics and replacement of glow plugs is rather difficult. That is why you should contact a service station if component defect signs have appeared. Performing such procedure requires professional equipment and car maintenance skills. Often, a special test bench is needed to define faults, and in case of breakdown of all glow plugs their control relay needs to be checked. Tightening torque of a new component, which is specified by the car manufacturer, should be observed when performing the replacement. Moreover, mounting procedure for new glow plugs varies for cars of different models and depends on special features of the engine installed.

Always replace the whole set of glow plugs.
It is advised to replace the glow plugs before the winter season starts.
Average operational lifetime: 60 000 – 80 000 km.

Types:

1. By type of connecting terminal:
   • threaded;
   • solid.
2. By coil material:
   • metal;
   • ceramic.
3. By coils quantity:
   • with a single coil;
   • with a double coil.
4. By heat range:
   • cold;
   • medium;
   • hot;
   • very hot.