These tools combined with an air hammer provide the hammering effect needed to loosen a stubborn glow plug. The flats on the bit provide the ability to use a wrench and apply the needed twisting force. Some machine work to the socket takes place in house to make sure it does not damage the Duramax glow plugs.
Using an impact wrench rather than this setup often just twist off the glow plug rather than breaking it loose.
Glow plug removal tool, January 10, 2018 By Ross (Rosetown)(Verified)
I used this tool to replace the glow plugs on my 2007 Classic 1ton duellie. The tool made the job easy and quick, without breaking off any of the glow plugs. As I bought this truck used, I didn't know when or if the plugs had ever been changed, so I went ahead and changed the full set. As I live in Saskatchewan, Canada where the winter temperature can and does reach - 42F, I need an engine to reliably start in the cold. The combination of a good block heater and working glow plugs ensures this happens every time! I would recommend this tool to anyone changing glow plugs as it ensures a damage free job!