yep they can come right out with the expansion of the ice.. the one on the back of the holden heads is a real pain to replace..Im talking old 186 here.. Ive even seen cars with hermetic ellements in the sump to keep the oil warm thus stopping water freezing. they then have to be plugged to the power when parkeds for the night....dont think you'd want to loctite them in if you ever go anywhere real cold like a ski holiday.. have used grease b4

My engine is an 1100 so I presume it still has 4 welch plugs.
Also the welch plugs fitted are lens type.
Do I have to put the same type back in or can I use the cup type