Glow Plug
WARNING: This page is about a different car, the 2018 Nissan Titan XD. However, it is still accessible from the selected car via links, so may be relevant.
The glow plugs are threaded into the tops of the cylinder heads above each of the eight cylinders. A tapered area on the lower portion of the glow plug mates with the taper in the cylinder head to seal the glow plug opening. When energized by the glow plug control module, the glow plugs can reach temperatures over 816° C (1, 500° F) within two seconds. This extra heat within the cylinder helps promote combustion of fuel when ambient temperatures are low.