Abstract: An engine block heater adapted for insertion through an opening in the block wall of an internal combustion engine has a novel arrangement for securing the heater within the opening of the block wall. The heater includes a plug member having a heating element, an adjustable screw and a fastening assembly attached to the screw and extending from one side of the heater into the interior of the engine block. The adjustable screw loosely passes through the plug member for adjusting the position of the fastening assembly. The fastening assembly comprises an elongated flexible bar and a rigid member. The flexible bar has the ends thereof normally biased such that one surface of the bar is flat and the distance between the ends is greater than the diameter of the block aperture. The flexible bar is capable of bending in opposing directions to reduce the distance between its ends and facilitate the insertion of the flexible bar through the block aperture.

Abstract: An engine block heater adapted for insertion through an opening in the block wall of an internal combustion engine has a novel arrangement for securing the heater within the opening of the block wall. The heater includes a plug member having a heating element and an adjustable fastening assembly extending from one side of the heater into the interior of the engine block. The fastening assembly passes through the plug member for adjustment from outside the block. A spiral spring is further included having its center positioned in fixed relation with the fastening assembly. The spring spirals towards the one side of the plug member. Additionally, two wing members are mounted in pivotal relation with the fastening assembly through an intermediate support member threadably mounted on the fastening assembly. The wing members have an inverted V shape with respect to the one side of the plug member when positioned within the spiral so as to facilitate insertion of the plug member into the aperture.