Wynn'sCrystal Clean & Protect - Additive for Use with AdBlue - Prevents Crystallisation in SCR Systems - Enhances Diesel Emission Control Performance - 125ml

I got the EML light and “cannot read Adblue tank” message on my C class. Adblue tank was almost full. I added TWO containers drove in high revs and a couple of long drives. The EML light went out and the Adblue reading was corrected. Worth every penny. If you have not researched Adblue Mercedes problems be prepared for a shock if you need a tank/pump and NOX sensors. You may need the EML reset done by a merc independent with the xentry reader.

I have a Mercedes GLE with a 32 litre Adblue tank. I added this to an approximately 2/3rds full tank, so slightly under dosed (product is meant to be for 15L).Car has 70,000 miles on the clock, so wanted to start cleaning the components, to try and prevent costly repairs (which anyone with a Mercedes will know can be extremely high).I can’t say it made any difference to the drive, or noticed any exhaust difference, but I was using this as preventative rather than cure.The price is very reasonable for peace of mind.Adblue additives are becoming much more common now (if you read motoring forums).Despite an earlier review saying it destroyed their Mercedes SCR system, it seems to be ok in mine.I regularly used Wynns diesel additives, so trust this brand a lot. Their products are very good overall, and they have been around for a long time, with mainly 5 star reviews.Seems like a good product, and hopefully it will clean the Adblue/SCR system, and prevent problems.I will be using with every Adblue top up going forward.

I had an engine fault code regarding my Adblue system. Car said I had about 600 miles before car won’t turn on. Very scary. Garages told me it could be very expensive repair. So I used this stuff hoping that my problems would get resolved.And to my surprise it did.Emptied it in my Adblue tank.. drove for around 70 miles and job was a good one.Turned out to be a blocked def injector which this stuff cleaned up. And now no more fault codes as it went away on its own. I will keep using this Crystal Clean & Protect on every Adblue refill.

This stuff works. Took 3 bottles, but the BMW "adblue system failure" message disappeared after a week. Use this if your car is more than 3 years old.

Now I don’t know if this is working or not but it came quick and very well packaged. I used it in my car and before now I’ve had the adblu light come on but since having it in the tank and gone through the system the light hasn’t come back on so hopefully it has helped fix it. The last abundant cost over £1200 so great value for money in my eyes

I promised myself if this worked i’d post a review to help others who may have the same issue. Audi A4 Sports Ultra with a P20E800, reductant pressure too low alarm. It said the dreaded “650 Miles Left” even though the adblue was full. This happened 3 times over the space of a month, then went away on its own.Took it to my usual garage who advised it’s an expensive repair. They suggested this to see if it would work as it has in the past for others, since using I have had not one alarm and it has been over 2 months and roughly 1400 miles driven. Will continue to use this every time I refill my adlblue. Worth trying before a £1200 repair.

It's difficult to say if this works well unless tested in a lab but the idea makes sense so worth using just in case

I hoped it would unblock the injector, but this was probably wishful thinking. Fortunately, a helpful mechanic replaced the injector and forced the dpf to regenerate, fixing the emissions fault errors and count down. The main dealer was very unhelpful, claiming that the whole emissions system should be replaced, which could almost write off a ten year old van. Adblue systems are a massive problem after say 40k miles. This additive should be an essential part of servicing. The large commercial bottle clearly has the same product and is half the price by volume.