Do You Need a Locking Diesel Exhaust Fluid Cap for Ford Super Duty Trucks?

What is a Locking DEF Cap?

A locking diesel exhaust fluid (DEF) cap is an aftermarket cap that replaces the factory DEF cap on Ford Super Duty diesel trucks. DEF is required by diesel engines to lower emissions. The locking cap aims to prevent theft of DEF.

Why Do People Steal DEF?

DEF contains urea and deionized water. Thieves target DEF because urea has other industrial uses and can be sold illegally. DEF prices have also risen in recent years, making it more valuable to steal. Unfortunately, some people try to make money stealing DEF caps and siphoning trucks’ DEF tanks.

How Does a Locking DEF Cap Work?

Locking DEF caps use a variety of locking mechanisms to secure the cap. Most use a small padlock hole or latch system. Some even have combination dials or keys. This makes removing the DEF cap without the key or combination very difficult. It helps prevent siphoning thefts.

Do I Need a Locking DEF Cap?

If you own a 2011-2022 Ford Super Duty diesel truck, adding a locking DEF cap can be a smart precaution. Ford trucks have large DEF tanks, making them prime targets. And cleaning up after a siphoned DEF tank is costly and time consuming.

Most at Risk Ford Super Duty Years

2015-2022 Ford Super Duty trucks are most at risk. These years increased DEF tank size to over 8 gallons. More DEF per truck means more incentive for thieves to target them. But even 2011-2014 Super Dutys can benefit from a locking cap.

Where Are DEF Thefts Happening?

Regions with high diesel truck popularity are hardest hit by DEF theft. This includes the Midwest, South, and Mountain West. But trucks nationwide have been targeted. So even if your area hasn’t seen much DEF crime yet, it’s wise to stay ahead of the curve with prevention.

Choosing the Best Locking DEF Cap

The most secure locking DEF caps use sturdy, cut-resistant metals. Stainless steel offers bump and pick resistance for maximum security. Brands like Deflock and Safe-DEF make reliable caps.

Padlock vs Combination Locking Caps

Padlock caps allow you to add your own padlock. Combination caps have a built-in dial or push button lock. Padlock versions are most flexible for using high security locks. But combo caps avoid managing separate padlock keys.

Other Locking Cap Considerations

Look for full metal caps without rubber gaskets. All metal prevents cutting or prying. Match your truck’s factory DEF cap diameter to ensure proper fit. And read reviews to confirm reliable function in wet conditions.

Installing a Locking DEF Cap

Putting on a locking DEF cap takes just a few minutes. Make sure your truck is turned fully off before starting. Then locate the DEF fill tube on the driver side of the truck bed.

Step By Step Installation

The installation process includes:

1. Turning off engine and letting parts cool
2. Locating factory DEF cap
3. Twisting counter clockwise to unscrew factory cap
4. Removing old cap without spilling DEF
5. Checking and cleaning DEF fill tube threads
6. Installing new locking cap
7. Tightening by hand in clockwise direction
8. Testing lock function

Make sure not to overtighten the cap. Hand tightening is sufficient to create a good seal and engage the locking mechanism.

Adding a Padlock

If using a padlock style locking cap, thread the shackle through the holes after installing the cap. Use a high security padlock, like a disc lock or shrouded model. Choose a padlock that fits snugly through the cap’s holes without too much extra space.

Maintaining Your Locking DEF Cap

Periodically inspect your locking DEF cap for damage and function. Check for cracks or looseness indicating someone has tampered with it. Test the lock mechanism action when possible. Lubricating the lock can help prevent corrosion.

What to Do After Theft

If your locking cap fails and allows DEF theft, check with your truck insurance about filing a claim. You may also need to replace emissions components damaged by contamination. And install a new, heavy duty locking cap to prevent repeat targeting.

Protecting your diesel pickup from costly DEF theft is straightforward with the right locking cap. Investing in a good quality locking cap now can avoid major hassle and expenses down the road. Do your diesel truck a favor by keeping its DEF tank sealed off from thieves.

FAQs

Do I really need a locking cap for my DEF tank?

If you own a 2011 or newer Super Duty, especially 2015 and up, adding extra security is wise. DEF becomes more tempting to steal as prices rise. And cleaning out contaminated tanks is expensive.

Will a locking cap cause issues when refilling my DEF?

High quality locking caps are designed not to interfere with properly refilling your DEF tank. Just make sure to get one sized correctly for your truck's fill tube opening.

What locks work best with padlock style caps?

For maximum security, use case-hardened padlocks like disc detainer or ball bearing models. Avoid standard master locks. And choose a lock body size that fits tightly through the cap holes.

Should I get a stainless steel or aluminum locking DEF cap?

Stainless steel caps offer the very best cut and pry resistance. The small added cost provides much more durability and security than aluminum options.