Locking DEF tank cap
Freshman User
Joined: Jul 2017
Posts: 39
Likes: 3
From: Sammamish
I haven't found any. The best mod (imho) I've found is this one:
https://www.ford-trucks.com/forums/1...tructions.html
https://www.ford-trucks.com/forums/1...tructions.html
Hotshot
Joined: Oct 2015
Posts: 19,689
Likes: 12,812
From: Wyoming
The Stant catalog still shows only Superduty trucks up through 2016. I have a Stant locking cap for the diesel but nothing for the DEF.
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Tuned
Joined: Sep 2017
Posts: 298
Likes: 2
Were you able to reuse the cap tether on your locking cap?
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Hotshot
Joined: Oct 2015
Posts: 19,689
Likes: 12,812
From: Wyoming
Hey, I said I have a cap for the diesel side. I didn't say that I installed it. 
It's still sitting in the box which is in the back seat of the truck. It's protecting the back seat quite well. I'll get around to installing it sometime within the next 10,000 miles.
It's still sitting in the box which is in the back seat of the truck. It's protecting the back seat quite well. I'll get around to installing it sometime within the next 10,000 miles.
Posting Guru
Joined: Feb 2018
Posts: 1,555
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There is no flange on the 10510D Stant cap, so, no, you can't retrofit the tether.
I put the locking diesel cap on mine not because I'm concerned about siphoning (which is just about impossible to do with the check ball in the filler) but to make sure anyone who got the idea to pee in my tank...you know, just for fun, would not be successful. No, there's no one that I know of in the neighborhood who would contaminate the fuel tank, but you never know. Besides, that kind of peace of mind is cheap at under 20 bucks. So, nothing goes into the tank that I didn't put there.
I put the locking diesel cap on mine not because I'm concerned about siphoning (which is just about impossible to do with the check ball in the filler) but to make sure anyone who got the idea to pee in my tank...you know, just for fun, would not be successful. No, there's no one that I know of in the neighborhood who would contaminate the fuel tank, but you never know. Besides, that kind of peace of mind is cheap at under 20 bucks. So, nothing goes into the tank that I didn't put there.
Tuned
Joined: Sep 2017
Posts: 298
Likes: 2
There is no flange on the 10510D Stant cap, so, no, you can't retrofit the tether.
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Kromer
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Feb 26, 2017 07:22 PM