4.74.7 out of 5 stars
46 product ratings

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Would recommend95% agree

Good value95% agree

Good quality95% agree

43 reviews

by Top favourable review

Does what it says on the label

I'm a born sceptic, my main hobby is classic cars, well pre 2000. I cut these diamonds in half for my strimmer, hedge trimmer, petrol mower etc and they really work, I've put them in my cars, and great, they work tidy. The following spring, I leave the petrol in from the previous year, and they start straight away, and the same for my cars and motor bikes.Read full review...

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by Top critical review

No evidence it works

The big problem with this product is as far as I can tell, there is no conclusive scientific evidence that it has any beneficial effect, I did ask the supplier.
I purchased it to neutralize gelling of petrol over the winter due to the presence of ethanol although I have read that the Super unleaded petrol I use is not required to contain ethanol.
I do use Millers VSE treatment or Dipetane which is much cheaper and claims to help with lubricating valve seats, preventing deterioration of the fuel and has a scientific study from the University of Ulster available as a download. Read full review...

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by

Fuel Diamond

The product was recommended by a friend who owns 2 Ford Cortina MK2's (a Lotus & a 1600E). I 'fitted' it (dropped into full fuel tank) some 2 1/2 weeks ago and have noticed (I think) better running and improved consumption in my 1987 Saab 9000 2.3 Auto Griffin. The fact that it lasts for 5 years is a bonus.Read full review...

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by

It Works

I have been using this product in several bikes and classic cars over the last 20 or so years. I continue to buy them so on that basis, I’m convinced that they help prevent fuel deterioration. I do also use a fuel additive as a backup.Read full review...

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by

Here's hoping, worked for unleaded

Looks Good,

Had these in an old classic car years ago before having it converted to unleaded. When seats were changed they were undamaged so lets hope they stop the devastation E5 caused in my motorbike tank whilst off the road due to the pandemic.

See photos of tank damageRead full review...

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by

Unbelievable but true.

I have been using tin catalysts since the mid 1980's. I could not believe that all that was claimed could be true but if you don't try it, you cannot judge. The catalyst stopped engine pinking, improved the M.P.G. and caused absolutely no problems. I have used these catalysts in every vehicle, including Diesels and L.P.G. and always with the beneficial results. My cars have never failed an MOT on exhaust emissions.
A simple example of the effectiveness is with lawn mowers (Petrol). After the five month winter layup, having a fuel diamond in the tank and just leaving the petrol well alone, on resuming the grass cutting the mower started second pull. Stale petrol had previously made the mower very difficult to start and when it finally would start it ran badly until the next re-fill with fresh petrol. This situation was only getting worse with the current addition of Methanol to petrol, several other undesirable effects were happening, but now, with the tin catalyst, all those pestilential side effects have vanished. I am not associated with the vendor in any way, my statements are direct observations from me.
During the War, Rolls Royce had to devise a tin catalyst to be used in aircraft being used in Russia. If it saved the bacon over there it is more than good enough for me.
As a bonus, when the catalyst is simply dropped in the tank, there is no further maintenance and it lasts almost indefinitely.Read full review...

by

What an amazing product!!

I wish I had discovered this years ago as it transformed my Vw van. It is brilliant

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by

i have been using these diamonds for some years now yamaha fired up today with year old same petrol

because like ronseal it does what it says on the tin thankyou

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by

worth trying

only had fuel diamond in car & motorbike fuel tanks for short time, so can't give proper review. only time will give true results. all i can say at this time is so far all is good.

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by

fuel diamond

it looks simple enough and is well made, ive put it in my tank the bike still rides well,wont know if it works properly till next year as its a preservative item

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