Tank Warden™ for ’11-22 Super Duty – ETA: Mid Oct. Group Buy


SKU: Tank Warden Category:


Tank Warden is our industry-leading, USA made, locking cap kit that protects your investment and prevents bystanders from contaminating your Diesel fuel and DEF systems, potentially saving you thousands in expensive engine and emissions related repairs.

Each cap incorporates a highly manipulation resistant, quarter-turn lock cylinder that is prominently used in the casino industry. We opted to choose a lock that doesn’t use a wafer or tubular design, because those designs are insecure. Other locking caps require a cumbersome lock and unlock process and don’t utilize a real key and lock cylinder.

The caps incorporate an innovative design we developed and are incredibly easy to use. We even include an easy to use cap holder; no more messing with tethers! Unlike other locking caps that are tedious to use, you will find ours a joy to use.

Kit Contents

  • Three keyed-alike keys. One for you, your spouse, and a spare!
  • One locking green, laser engraved, Diesel fuel cap
  • One locking blue, laser engraved, DEF cap
  • One black cap holder

2011-2022 Ford Super Duty Diesel pickup trucks only. Not designed for cab and chassis trucks. Designed for trucks that have the OEM large, rectangular fuel door/pocket with the two OEM filler necks located within.

We cannot sell the Diesel cap by itself. Kits will include Diesel and DEF caps. 

Each kit is keyed uniquely from other kits, and therefore multiple kits within the same order cannot be keyed alike for multiple trucks. For large fleets interested in identical locksets, please contact us here so we can discuss your requirements. 

Ford and Super Duty are registered trademarks of the Ford Motor Company. Subtle Design has no affiliation with Ford or its partner companies.

Additional information

Model Year

2011-2016, 2017-2022

Body Style


Fuel Type



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