Jeep Wrangler/YJ 1987-1995 Repair Guide

Pressure/Vacuum Fuel Tank Filler Cap


The fuel filler cap is equipped with a two-way relief valve that is closed during normal operation of the vehicle. The relief valve is calibrated to open only when conditions equal or exceed 1.5 psi (10 kPa) of pressure or 1.8 in. Hg (6 kPa) of vacuum. When the vacuum or pressure is relieved, the valve returns to the closed position.