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DEF Crystal Clean™ Diesel DEF & SCR Emissions System Cleaner

  • Improves DEF Diesel Exhaust Fluid
  • Clears P20EE & Other OBD Codes
  • Restores SCR Selective Catalyst Reduction
  • Cleans DEF Injector, Sender, Guaranteed
Your best weapon against SCR white crystal buildup.


Are you tired of dealing with white crystals clogging your diesel vehicle’s Selective Catalytic Reduction (SCR) system? It’s a problem many diesel owners don’t address before it’s too late. Introducing Rislone DEF Crystal Clean™ – the ultimate solution to keep your diesel engine running smoothly and efficiently. Years of research has led us to this formulation, and there’s nothing else like it on the market.

See below for more details.

Product Support:

Product Details

Part Number: 4784

Dosage: For car or small SUV - 3 to 5 gallon tank use 1/2 bottle. For light truck to mid-size to large SUV - 5 to 9 gallon tank use the full bottle.

Size: 11.8 FL OZ (350 mL)

SDS / Tech Info:
4784 SDS Open Download
4784 PDS Open Download

Frequently Asked Questions

Additional Product Info

RISLONE® DEF CRYSTAL CLEAN™ Diesel DEF & SCR Emissions System Cleaner is a proprietary blend of DEF (Diesel Exhaust Fluid) / AdBlue® compatible cleaning agents and surfactant detergents specifically designed to be safe to use and work on SCR (Selective Catalyst Reduction) systems.

DEF Crystal Clean gives a cleaning effect on the entire SCR system by working to dissolve the white crystal deposits that form in the tank, pump, heater, sender, lines, injector, decomposition tube / reactor and mixer. These deposits can interfere with the normal operation of the SCR emissions system and engine, increasing fuel consumption and reducing engine power. This reduced power can lead to operating in limp mode where the vehicle will drive slowly, or become undrivable. This process restores function and with regular use maintains efficiency of the SCR.


  • Excellent for diesel vehicles driven regularly at slow speeds, low loads, short durations or make frequent stops as these are more prone to having the problem of crystallization deposit build up in the SCR system.
  • Regular use every 5,000 miles not only keeps the system clean, but works to prevent the white crystallization issues from returning.
  • Will not void manufacturer’s new vehicle warranty. Specifically designed and safe to use on vehicles which have DOC catalytic converters, DPF particulate filters, SCR selective catalytic reduction devices, ASC ammonia slip catalyst or DEF / AdBlue systems.
  • Works with all AdBlue, Aria 32 (Automotive Nitrogen Oxide Liquid Reducing Agent), AUS 32 (Aqueous Urea Solution), BlueHDi, BlueTEC®, Cummins®, DEF UREA, Duramax®, EcoDiesel®, PowerStroke®, TDI® Clean Diesel, and many more.



  • Avoid Costly DEF System Repairs
  • Improves Emission Component Life
  • Restores SCR Selective Catalyst Reduction Performance
  • Cleans Crystal Deposits, Guaranteed
  • Works with all UREA DEF / AdBlue Fluids
  • Restores Optimal DEF Injector Spray Pattern




DEF Crystal Clean is specifically designed to only be installed in the Diesel Exhaust Fluid / AdBlue tank which usually has a blue cap. Do not add to the diesel fuel tank.
Light Truck or Mid-Size to Large SUV
5 to 9 gallon tank capacity install full bottle into DEF tank.
Car or Small SUV
3 to 5 gallon tank capacity use approximately 1/2 bottle.
Medium and Heavy Duty Diesel Trucks
10 to 20 gallon tank capacity use 2 bottles.
Pour DEF Crystal Clean into mostly full DEF tank or add and fill tank with diesel exhaust fluid. If light is still on after 250 miles or a few days of driving, second application may be required, or mechanical attention is needed.

Works with all approved diesel exhaust fluids. Some vehicles use a special filling adapter to install DEF / AdBlue into the tank. For those vehicles use special funnel or pour into mostly empty DEF / AdBlue bottle and install in system.


AdBlue® is a registered trademark of VDA Verband der Automobilindustrie



Available At:

Rislone products are available where auto parts are sold.