As the colour of the tips of its glow plugs might give the impression that they are somehow not ‘new’ products, DENSO Sales Manager, Kevin Peacocke, shares why the tips have a grey/blue colouring.
DENSO is a glow plug OEM; it also supplies the independent service and repair sector. Its aftermarket range is produced on the same production lines as OE so can be relied on by automotive technicians and motorists alike.
Although this statement should be enough to reassure those with any concerns over the providence of its glow plugs, to clarify the situation and provide peace of mind for both installers and its valued motor factor customers throughout Europe, DENSO is very happy to explain why its glow plug tips have this colouration.
In common with many highly engineered products, the manufacture of glow plugs is a complex process, particularly the production of the glow tube, which, when installed, can be heated up to temperatures above 800°C within seconds. This is needed to ensure a quick and reliable start when the engine is cold, and to reduce emissions when it is running.
As this heating element is the most critical component of the glow plug and allows it to fulfil its role in the ignition system, its functionality has to be verified during the production process.
It is for this reason, that at the end of the production line, the performance of each glow plug is thoroughly tested to ensure that it is working in accordance with the given specification, including its heat-up time and the temperature it needs to reach. It is this in-line production test that causes the glow plug’s tip to take on this grey/blue tone. This colouration is due to the oxidation of the metal, which is accelerated by the high temperature it is subject to during the test, but it does no harm to the glow plug, nor does it degrade its performance.
Therefore, rather than being something of concern to technicians when opening the box, it should be regarded as a sign of reassurance, because it indicates that the glow plug they are about to fit has been tested and works according to its given specification. It will perform as they’d expect from an OE part supplier.
DENSO’s considerable research and development investment has helped it to pioneer increasingly efficient, powerful and reliable diesel engines with minimal emissions.
DENSO Aftermarket, which naturally draws on this expertise, subsequently offers a comprehensive, OE quality all-makes glow plug portfolio – one that benefits from cutting-edge technology and provides outstanding start-up performance with extended post-heating temperatures, to deliver a complete competitively priced solution.