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

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 my doubts! Had engine fault code P20E800, reductant pressure too low.Just bought the car, 81k miles and from service history, it's not been well looked after, so presume adblue crystallising within the system.Topped up with a fresh 10l adblue, followed buy a full bottle of this.1 week later, my fault is cleared and not recurring any more.I'll use this at every adblue top up now.Highly recommend.

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.

Happy with product

I have been using this product on my diesel car for a year, today I took of the ad-Blue injector to check how clean it was due to a engine light coming on & there was a remote chance a blocked injector could cause the problem. When I took off the injector me and a friend who assisted me under the car were surprised on how very clean it was including the hole it fits into, considering the injector has been on the vehicle from new and covered over 78K I can only put this down to this product working as I have never seen this before.

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.