Successfully replacing ceramic glow plugs (Fig. 1) in diesel engines requires carefully handling of the plugs and following the proper service procedures in order to prevent potential performance issues.
Fig. 1
Here are a few tips on ceramic glow plug replacement on the 1.6L I4 diesel engine (RPO LH7), Duramax 3.0L I6 diesel engine (RPO LM2, LZ0) and Duramax 6.6L V8 diesel engine (RPO L5P, L5D) available in 2017-2019 Cruze; 2017-2024 Silverado 2500/3500, Sierra 2500/3500; 2018-2019 Equinox, Terrain; 2019-2022 Silverado 4500/5500/6500; 2020-2024 Silverado 1500, Sierra 1500; and 2021-2024 Tahoe/Suburban and Yukon models.
- Measure the resistance of a new glow plug. An open circuit in a glow plug indicates that the glow-plug tip is broken and should not be installed in an engine.
- Do not install a glow plug into an engine if the glow plug has been dropped.
- Pull on the tip of a new glow plug before installation. Be sure your hands are clean before handling the glow plug.
- Always use the EN-52074 Glow Plug Bore Reamer (Fig. 2) when replacing a ceramic glow plug on the 1.6L, 3.0L and 6.6L diesel engines. A glow plug hole bore cleaning tool will remove the soot built up on the inside of the glow plug hole. Once a glow plug is removed, the soot collected in the bore must be removed. Otherwise, the soot could “side load” the new glow plug and induce a premature failure. The only exception to this is when servicing a glow plug on a 2.0L or 2.8L diesel engine.
Fig. 2
- Never use any type of grease or anti-seize compound on a new glow plug. Using any lubricant could lead to over-tightening of the glow plug.
- When installing a glow plug, make sure that it is in line with the glow-plug hole. Any side load placed on the glow plug could cause a crack in the ceramic, which would lead to premature failure.
- Do not use power tools to install a glow plug.
- Do not overtighten a glow plug. An overtightened glow plug could initiate a crack in the ceramic, leading to premature failure.
For more information, refer to Bulletin #23-NA-032.
Thanks to Larry Yaw
If the tip breaks during removal, remove the head to get the tip out. Proper installation plays a key role here. For the LML engine, the glow plugs use a steel tip.
Any tips for removing them from the engine without breaking them? Because that is the actual issue. Who is breaking them putting them in?? Also, have you seen the packaging the LML glow plugs come in? Bare plug in an empty box, no packaging, just free to rattle around as the union parts distribution warehouse workers play catch/drop with them