STPEngine Stop Leak for Petrol & Diesel Engines 300 ml, Improved Concentrated Formula, Conditions your Engine and Prevents Minor Oil Leaks, Mechanical Car Cleaning Products, Made in the UK

This is a good product that helps to clean out the petrol delivery system to your engine. Smoother running, more responsive engine, more mpg. Pour into your fuel tank every 4000miles. Simples! Recommended.

Great product, I was actually just about to re-order it. It helped my car so much, I have a small engine and my car didn't get much maintenance from previous owners - this product did it's job well. Great value for money, cleansed everything I could feel much more power coming out from that engine! Lasted about 4k miles. Highly recommended.

Good quality and good value

Why did you choose this product over others?:I don't normally use these products but the car wasn't running well. I put this in the tank and filled up with E5 petrol, after 80 miles or so thr car was running well and smoother. Very pleased with product

My Puma was running a bit rough and seemed to lack power, so I thought I'd give this a go. I've used Redex in the past but I thought I needed something a bit stronger. It had an effect pretty much straight away. For the next couple of drives, the engine seemed actually worse than before, but I assume this was a combination of the gunk being cleaned out and the engine adjusting to the fuel's octane rating being changed by the additive. After those couple of drives, the engine is back to how it should be, it's running smoother, take off is immediate and even fuel economy seems a little better. I'll definitely use this again, but probably every 6 months, instead of waiting for the engine to get gunked up again.

Arrived quickly from Amazon, we'll packaged. Put this in a full tank on my 2015 1.2 petrol DS3 w/103k on the clock about 2 weeks ago and so far looks good. My fuel gauge is digital and each quarter is split into 3 blocks, since I bought the car 2 1/2yrs ago I've been gauging fuel use by using the trip computer, trip 1 for each block and trip 2 for full tank, each block was going after about 28 miles, 30 at a push, so each quarter tank gave about 84ish miles, so a full tank was returning about 350 miles, my journeys are very much the same month to month, home-work-home, shopping or popping to MILs. Since I've put this in 2 weeks ago each block in the quarter of the fuel guage has been going off after 35 miles, so 105 per quarter so possibly signifying an increase of 70 miles or so for the full tank.Now in February I did have new tyres all round and a wheel alignment so the new fuel economy could be partly down to that but I have felt that the throttle response does feel much better, I've got this on subscription so planning to put this in my car and the wife's every other month and see how it goes but at first impressions it looks to be doing something positive

Bought this after reading the reviews and already trying traditional Redex to ‘cure’ a recurring Engine management light on an EPace. Nothing to report after using half a tank of fuel / long trip. 2 hours after our journey I reopened the Jaguar app to see the fault has now disappeared!3 stars until I know it stays off, but will use again in 4K miles.Edit… Engine light only stayed off 4 days! …but I’ve still half a tank of fuel with the additive in, so hopefully it clears again :s

I normally fill up with BP Ultimate but on a recent 3,000+ mile road trip knew I would have to fill up with regular 95 for large parts of the trip. I decided to buy the 5-in-1 treatment to mitigate using the regular unleaded, as opposed to thinking my engine specifically needed to be cleaned. For reference my car is a 2022 BMW M135i xDrive and had 16,000 miles prior to the road trip. At around the 2,000 mile mark in my road trip I added the treatment to a tank of regular unleaded. After using the treatment I achieved the best MPG I’ve ever had out of the car, 56.7mpg. Previously my best was around the low 50s. I will now use the treatment every few thousand miles. I am genuinely impressed.