For Rams with Diesel and DEF

Besides the flap, the fuel door also has a rubber seal. Doesn't block all dust out though. I bought the green fuel cap the day after I purchased my Ram. Don't need any dust getting in the tank.

These are all over the internet. You can find them on Geno's garage, and eBay. It's a good investment.

 

Has anyone looked for locking caps? Is this even a possibility? Sounds like you guys are describing an insert tube that has no threads. My neighbor has had diesel fuel stolen out of his truck now 3 times, plus a locking cap keeps away other foolish things out of the tank, like it did for me in college. They did manage to pick up my teacher's car and move it over a couple of isles in the parking lot. They also were trusted to another teacher's car for an errand, and that car ended up on the Music Theatre's stage when the curtain came back for a soloist and piano accompanist. Just a fun little story there! But I'd like to keep that fun out of the diesel fuel!

 

Think I seen these green caps with a key lock also. Check eBay, or genosgarage.com