Low Temperature Coolant Reservoir Cap Design With Air Gap For Hybrid Vehicles

The disclosed inventive concept provides a cap for a coolant reservoir that accommodates the expansion of coolant stored therein. The expanding coolant results from an increase in temperature and causes an increase in pressure to build within the coolant reservoir. The cap includes a base and a crown having an air-dome which extends upwardly therefrom. The base includes a passageway extending therethrough and in fluid communication with an interior cavity or an "air gap" formed in the crown. As the cap is positioned over an open neck of the coolant reservoir, by being screwed or otherwise fitted thereon, the interior cavity remains positioned above the neck. Thus, as the coolant within the coolant reservoir becomes heated and expands, the interior cavity provides additional space for the coolant to occupy and pressure to build within.