Which diesel fuel cap?

[CorbettO]

My diesel fuel cap was stolen. Do I replace it with a vented cap? Non-vented?

I have a 2001 bluebird TC FE 2905.

Thanks

[TJones]

My tank has vent port and the cap is not vented. Maybe look into a lockable cap. I'll be putting one on when my bus is ready to hit the road.

Ted

[Rivetboy]

My 91 BB 5.9 also has a vent in the tank and a non vented Locking fuel cap behind a locked fuel door.

[Rwnielsen]

I just have a screw on brass cap behind a locking door
98 TC 2000

[Mountain Gnome]

My cap is not vented, and the lock will jam if I lock it, and I have to turn the key with a pair of pliers. Seems to be the corrosion starting on the inside of the tank; the lock turns freely when the cap is not installed.

[rossvtaylor]

For our buses, the fill port and cap location is behind a locking door flap. But on our Freightliner ambulance, the fuel cap is exposed on the tank beneath the steps. We had to replace the cap with a locking one, to meet some convention show requirements in Austin, and we paid about $100 for a nice Stant locking cap. And even though it's a top-quality cap, it's a bit scary to use. The locking mechanism is a toothed cam and if you lock it, then someone (intentionally or accidentally) tries to unscrew the cap...or if they fire marshal tightens to make sure it's secure, the teeth grab the inside of the fill pipe and it's then very hard to unlock. Although I've not yet broken the key, it sure makes me cringe. If it weren't for the show requirements at some events, I'd skip the locking cap.

On a side note, a regular 2" threaded pipe cap works fine. But most "real" caps have meltable sections, in case of a fire I guess...