Jeep Wrangler/YJ 1987-1995 Repair Guide

Pressure Relief/Rollover Valve


See Figures 1 and 2

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Fig. Fig. 1: Pressure relief/rollover valve location

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Fig. Fig. 2: Pressure relief/rollover valve operation

The fuel tanks of all vehicles are equipped with two pressure relief/rollover valves. The valves relieve fuel tank pressure and prevent fuel flow through the fuel tank vent hoses in the event of vehicle rollover.

The valves consist of a plunger, spring, orifice and guide plate. The valve is normally open allowing fuel vapor to vent to the canister. If the bottom of the plunger is contacted by sloshing fuel, the plunger seats in the guide plate preventing fuel from reaching the canister.

If the vehicle should roll over, the valve is inverted and the plunger is forced against the guideplate, preventing fuel from flowing through the vent tube.


  1. Disconnect the battery negative cable.

If the engine has been run recently, allow it to thoroughly cool in order to prevent a fire hazard with fuel contacting hot exhaust system components.

  1. Remove the fuel filler cap.
  3. On 1991-95 vehicles, which are equipped with Multi-Port Fuel Injection (MFI), the fuel system is under constant pressure and MUST be released properly. Please refer to the Multi-Port Fuel Injection (MFI) section of Chapter 5 and follow the Fuel Pressure release procedure.

DO NOT allow fuel to spill on the intake or exhaust manifolds or any hot component. Use rags to absorb any spilled fuel and dispose of the rags properly.

  1. Drain the fuel tank dry using a siphon pump.
  3. Raise and support the vehicle safely.
  5. Remove the fuel tank. For details, please refer to the procedure in Fuel System .
  7. The rollover valve is seated in a grommet. Pry one side of the valve up and twist to remove the grommet from the tank.
  9. Installation is the reverse of removal.
  11. Start vehicle and check for leaks.