This disclosure provides an ignition coil for a spark ignited internal combustion engine. The ignition coil includes a coil body having an outer surface and internal windings coupled to a connector. The ignition coil also includes a housing surrounding the coil body. The housing has an outer wall spaced apart from the outer surface of the coil body thereby forming a gap between the outer surface of the coil body and the outer wall. The outer wall includes an opening in flow communication with the gap.