Purpose and Specifications

LIQUI MOLY DEF Anti Crystal Additive Concentrate (21800) is a premium 2.5-liter solution designed to protect your diesel vehicle's SCR system from harmful urea crystals. Add just 25 ml per 10 liters of AdBlue to prevent deposits in the tank, lines, and injectors, ensuring smooth operation and avoiding costly repairs.

• Lowers freezing point from AdBlue's -11°C to -16°C, keeping your system fluid in cold weather down to -16°C.
• Optimizes spray pattern for better exhaust cleaning and fuel efficiency.
• Prevents blockages in pumps and nozzles, especially during short trips, city driving, or vehicle downtime.
• Long-lasting protection: One 2.5L bottle treats up to 1000 liters of AdBlue, ideal for fleets or high-mileage drivers (every 10,000-20,000 km or annually).

Shelf life is 3-5 years when stored cool and dry. Shake well before use to mix any settled particles.

When to Use / Replace?

Add after refilling your AdBlue tank during routine maintenance, like every oil change or 10,000 km. Use proactively if your truck or van sits idle for weeks, drives mostly short distances, or faces freezing temps below -11°C. Replace the additive mix when you drain and refill the AdBlue tank, typically every 1-2 years or 50,000 km depending on usage.

Practical tip: Ideal for Euro 6 diesels with SCR – keeps warning lights off and emissions compliant without workshop visits.

FAQ

Can I use this in any diesel with AdBlue?
Yes, it's safe for all SCR systems using 32.5% urea solution (AdBlue/DEF). Mix 1:400 ratio right after filling.

Does it fix existing crystals?
No, it's preventive only. For clogs, clean mechanically first, then add to protect.

How much for my fleet truck?
2.5L treats 1000L AdBlue – enough for 50,000+ km on heavy-duty vehicles.