Sucking sound when removing fuel cap

[Joe Mc]

Seems like the fuel tank isn't venting. Every time I remove the cap, even after a 20 mile drive, I hear a sound of air going in. For sure not pressure coming out. Is the cap supposed to be vented, or is there a vent on the top of the fuel tank module? Truck in signature, note fuel system.

Edit: Noticed fuel system isn't listed in signature, GFS-392 = walbro pump, spin-on filters (2) mounted along frame, big like kit.

 

[BigPapa]

Are you having an issue? I heard air a lot of times when I removed the cap on my ‘95 but never had an issue.

On your ‘99 there is a Vent/Rollover Valve in the top of the tank, Mopar number 52127666. I couldn’t find a part number for an OE cap, but all the aftermarket caps say vented.

 

[Joe Mc]

Thanks BP. No not having any issues, just that I've had this truck since 05/01, fuel system since mid 2003 and I don't recall hearing any sounds when removing the cap. A few years ago I, for some reason, got rid of the locking cap that I had for years and got another one (forget brand). I thought there was a roll-over valve on the module but wasn't sure if it was a "vent" as well. Will do a visual check of roll-over valve and guess I could just get a locking cap from Geno's Garage. Thanks again.