RunCool Hood Louvers are designed as a cost-effective way to cool hot police car engines. Releasing hot air rising from the engine can reduce parts and maintenance costs and result in fewer breakdowns. Hood Louvers can be especially effective in increasing durability and air conditioning efficiency for idling, static units such as those used for K-9s. They’ve been desert tested and used by the U.S. Border Patrol. New size large hi-flow models are available for Crown Vics, Tahoes, Expeditions, etc.