COMMON QUESTIONS

What is DEF crystal buildup and why is it harmful to my vehicle?

Diesel Exhaust Fluid (DEF) crystal buildup occurs when urea crystals form and harden inside the Selective Catalytic Reduction (SCR) system. This typically happens when DEF is exposed to high heat, air, or improper mixing conditions—causing it to dry out and leave behind white, chalky deposits. These crystals can clog the DEF injector nozzle, sending unit, lines, and other components of the emissions system.

Over time, this buildup restricts fluid flow and disrupts the precise spray pattern needed for proper emissions reduction. The result? Poor engine performance, increased fuel consumption, and even system failure—often triggering costly repairs, DEF-related warning lights, or engine derate modes.

Hot Shot’s Secret^TM Premium DEFender^TM is specifically engineered to clean existing crystal buildup and prevent new deposits from forming, protecting your SCR system and keeping your diesel engine running at peak efficiency. 

How often should I use DEFender^TM in my diesel vehicle?

For optimal protection, use Hot Shot’s Secret^TM DEFender^TM every time you refill your DEF tank. Simply squeeze 1 oz of DEFender^TM for every 2.5 gallons of DEF and pour it directly into the DEF tank or DEF cube during refilling. An 8 oz bottle treats up to 20 gallons of DEF.

Consistent use helps prevent harmful crystal buildup, keeps your SCR system clean, and reduces the risk of trouble codes or costly repairs. Be sure not to exceed the recommended dose.

Will DEFender^TM clear emissions-related OBD trouble codes?

Yes. Hot Shot’s Secret^TM Premium DEFender^TM is formulated to help resolve common emissions-related OBD trouble codes such as P20EE, P204F, P207F, P20E8, P218F, and P20EF. These codes are often triggered by poor DEF dosing, injector clogging, or SCR system inefficiency due to crystallization.

By cleaning out hardened deposits and restoring proper DEF flow and spray pattern, DEFender^TM supports the SCR system’s ability to reduce NOx emissions and can help clear or prevent these codes from reoccurring. For persistent codes, we recommend combining use of DEFender^TM with a full diagnostic scan to confirm the root cause.

Can I use DEFender^TM with any brand of DEF?

Absolutely. Hot Shot’s Secret^TM Premium DEFender^TM is compatible with all brands of Diesel Exhaust Fluid (DEF) and is safe for use in all diesel vehicles equipped with a Selective Catalytic Reduction (SCR) system. It’s designed to integrate seamlessly with your DEF—no matter the manufacturer—without altering DEF composition or performance. Whether you’re topping off a pickup truck or a Class 8 rig, DEFender^TM works alongside your current DEF supply to enhance system reliability.

Will DEFender^TM affect my DEF sensors or system warranty?

No. DEFender^TM is made with system-safe chemistry and is non-corrosive, non-toxic, and free of metals that could damage sensors or SCR components. It will not interfere with DEF quality sensors, NOx sensors, or your onboard diagnostics system when used as directed. While warranties vary by manufacturer, the use of DEFender^TM does not alter the chemical composition of DEF in a way that violates DEF specifications (ISO 22241), and it is triple filtered and safe for regular preventative use.

What are the signs that I need to use DEFender^TM?

Signs of DEF system issues that may benefit from DEFender^TM treatment include:

A strong ammonia or chemical odor near the tailpipe Active DEF or emissions warning lights on your dash Decreased fuel efficiency or engine power Visible white buildup near the DEF injector OBD trouble codes related to the SCR/DEF system (e.g., P20EE, P204F) Excessive regeneration cycles

Using DEFender^TM proactively helps prevent these issues, but it can also be used reactively if you’re experiencing symptoms of DEF crystallization or dosing inefficiencies.

Can DEFender^TM be used in cold weather?

Yes. One of the key benefits of DEFender^TM is its ability to lower the freeze point of Diesel Exhaust Fluid, making it ideal for cold-weather diesel operation.

How is DEFender^TM different from other DEF additives?

Hot Shot’s Secret^TM Premium DEFender^TM stands out with a multi-function formula that not only prevents DEF crystallization but also cleans existing deposits, adds critical lubricity for DEF pumps and injectors, lowers freeze, and helps clear common emissions-related trouble codes. While some additives focus only on freeze protection or deposit prevention, DEFender^TM delivers a complete, science-backed solution that protects and restores the entire DEF/SCR system—making it a superior choice for long-term emissions system health.

Can I use DEFender^TM in off-road or agricultural diesel equipment?

Yes. DEFender^TM is safe and effective for use in all diesel equipment that utilizes a DEF/SCR emissions system—including off-road machinery, tractors, combines, construction equipment, and generators. Whether your equipment operates in harsh environments, high-load conditions, or cold climates, DEFender^TM offers reliable protection against crystallization, injector issues, and system faults. Just follow the same dosing instructions: 1 oz per 2.5 gallons of DEF.

MONEY BACK GUARANTEE

HOT SHOT’S SECRET STANDS BEHIND ITS PRODUCTS WITH THE BEST MONEY-BACK GUARANTEE IN THE INDUSTRY

No other diesel oil or fuel additive has a better guarantee than Hot Shot’s Secret products. If our products do not deliver as promised, then we will give you your money back. End of story.