Rislone 4784 DEF Crystal Clean™ Diesel DEF & SCR Emissions System Cleaner, 11.8 oz

Cleans theft system and gets rid of problems. I have used this on a Peterbilt and a Freightliner

As always, I'm skeptical when it comes to product performance—but this one? Amazing.I never owned a diesel until I bought my '21 GMC HD2500 Duramax. I love it, but man, diesel engines demand preventive maintenance. You can't wait for things to break—you’ve got to stay ahead of it with products that help reduce or even prevent issues.This particular product is excellent.Since the day I bought my truck, I’ve had nonstop problems with the DEF tank sensors sticking. Sometimes it would show full when I knew it wasn’t, and other times it claimed to be half empty right after a fresh fill-up. Totally unreliable.And what did the dealer say? “It’s inadvertent.” That word should be banned—it’s just an excuse to ignore a real problem.Let me tell you—this product works. Period. And it worked fast, too. Absolutely amazing.

Excellant product. I highly recommend it.Instead of my truck telling me I needed DEF fluid it threw a code and immediately started to count down to miles left before a reduction in speed. Then I remembered I is DEF that was old. When I looked online I found a YouTube video explaining this product. I put a half bottle dose into the 5.5 gallon DEF tank in my 2016 GMC Canyon and within a day the engine light went off and I was back to normal. I put the second half of bottle in the next DEF fill up. Since then I ran NJ to Florida twice with no issues.

Cautious user. Truck sat most of Winter, so really my cause & effect with the DEF crystallizing. Cleared my DEF code 3 times. What a pain in the ass. Filled my DEF tank 100% on 2017 Ram & ran to Colorado ~ 1000 miles. Dilution & keeping the DEF tank >50% with this first treatment seams to be working. I bought a DEF injector valve on Amazon & will change it out. The challenge with this little valve replacement is the possibility of damaging the threaded mounts on the exhaust tailpipe. PB Blaster & 10mm box end wrench!! Seems to be a good product! 😀

I have a RR Sport I rely on this. If you have a diesel engine and don’t drive a lot of long distances or high speeds, you need this so your DEF filter doesn’t clog.

Bought to remove crystals from a DEF system with a heater trouble code. 2013 X5 35D - research indicated the heater code is created when crystals build up on the heater and I attempted to use this to remove them. 600 miles later and the code comes back as soon as you clear it. Might work for other issues but not for this one.

Kept having DEF related issues and cleaned up my tank/system quickly. L9ve how the bottle was designed to pour in the tank without a fuel. Will be buying again.

I added a dose of this to my tank as a preventive measure to keep everything in good working order. Never had a problem with anything prior to using this stuff. The "Poor DEF quality" warning light was displayed soon after i added this to my tank. After running the truck until DEF was around 1/2 tank, I topped the tank off with DEF and the warning light went away on its own and I haven't seen it since. I never noticed any actual problems but my Duramax L5P didn't like it. It could have been the DEF that I added when I added the product--i have no way of knowing. I've always bought Peak BlueDEF and never had a problem except when i mixed it with this.