Diesel technology

Time and again there are discussions in forums about removing a glow plug and connecting it to an electrical source to test whether it still glows. Such "testing methods" can cause serious injuries due to burns!
Also, incorrect installation of glow plugs can damage both the glow plug itself and the engine.
Therefore, testing and replacing glow plugs should always be left to the experts, they have the necessary knowledge and the right equipment.

Contact Information

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G.W. Dale Ltd
139 Newcastle Street
Stoke on Trent

Phone: +44 (0) 1782 837 665
Fax: +44 (0) 1782 839 550
What is a Glowplug?

Diesel engines rely on the compression of gases to achieve combustion. This is fine in some conditions, however when the outdoor temperature is low, or the engine's cold, glow plugs are required to assist starting. Glow plugs reach temperatures of around 850°C and preheat the engine in readiness for combustion


Cross Section of a typical glow plug


Glowplug installed in the engine


Glowplug Defects

A faulty glowplug can often point to other faults with the engine


Such a defect normally arises if the point of injection time or spray pattern is not set correctly, the wrong fuel quantity is injected or oil penetrates into the combustion chamber.

Over Voltage
over voltage

A "blown-out" glow tube is the result of using the wrong glow plug , the control unit is defective or the alternator generates too much voltage.

Broken glow rod
broken rod

If the glow rod has broken, it may be a result of the incorrect point of injection time, the wrong spray pattern or a poorly set flow rate.