94 GTX Black Pressure Relief Valve Question

[diggitydesigns]

On the black pressure relief valve that feeds out the little elbow just below the bumper trim, is this supposed to allow air to flow through both ways? From what I gather its only supposed to open one way? When I blow through mine I can blow a little air both ways. Can some one elaborate on this a little. Thanks.

 

[JJinSC]

Yes this is a pressure relief valve. It should not let any air or water in, but when the fuel system gets pressurized due to fuel expansion to more than 3psi it will let pressure out. You can try cleaning it with soapy water and compressed air, but I have found that they get gunked up over time from the fuel line degradation (yes some gas can ooze out these valves sometimes when the tank is full in the hot sun. The replacement part is pretty reasonably priced. I would just replace it and as long as you have replaced your fuel lines you'll get another 15+ years out of it.