18-Up Wrangler JT/Gladiator 3.6 Liter Crankcase Vent System Kit TeraFlexThe TeraFlex JL JT 3. 6L: Crankcase Vent System Kit (CVS) prevents oil from being drawn into the intake by engine vacuum while driving on extreme inclines. This kit adds a second PCV valve to the front of the engine via an oil fill cap adapter and T fitting. Adding a second PCV valve at the opposite end of the engine ensures only air is allowed to enter the crankcase vent system regardless of engine orientation while off roading. A Ball Check Valve