– STP GST50400EN 0.4L Complete Fuel System Cleaner 400ml Petrol Additive

I've used STP products for a long time, especially the Complete Fuel System Cleaner, which I've been using for over 10 years now. I use it on my wife's car, a couple of weeks before the MOT, to ensure the engine is running smoothly and emissions are low. Its never failed an MOT on emissions ever, in the 10 years I have been using it. Very simple to use-just add it to a full tank of petrol (there is a diesel version-so make sure you buy the correct one) via the petrol tank. Easiest way is once you have taken the lid off and removed the foil cover, is to place a funnel into the petrol slot, which keeps the metal flap (which opens when you push fuel nozzle in and springs close when nozzle is removed) open, or carefully keep bottle upright until you are ready to pour in, then quickly push the narrow top of the bottle into the petrol flap, pushing the flap down as you go, this ensures all the cleaner enters the tank. If you pour slowly, you will have to wait for small amounts of the liquid to go into the tank, via the closed flap, which takes an age to do. Don't fill up the tank with petrol again, until you get onto your 'red' warning or 'low fuel' warning light/indicator comes on, this is to ensure you dont dilute the cleaner with extra petrol and give it enough time to work its way through the engine. You should notice after a few drives (once fuel has had a chance to be cleaned) that you get a bit of 'extra power' when you put the accelerator down. This does depend on how clogged your injectors were in the first place.

Not used my car much at all during the pandemic and when starting to use it again I had rough idle, rough ride, problems starting the car and the odd misfire. I suspected dirty injector’s so put a bottle of fuel line cleaner in and also the bottle of injector cleaner and filled my fuel tank with good fuel. After a quarter of a tank, all problems where solved. Car runs smoothly, I’ve got more power and it starts everytime. I’ve filled my tank a few times since using this and the car is still working without any issues. I’ve bought some more to use again in 6 months and will continue to use for the lifetime of the car to keep it running nice. I’ll only use premium fuel from now on as well, no more rubbish from the supermarket.

Updated review. In summary it helped low-end performance but did not improve fuel economy for same *driving style*. Do these cleaners work? This is an emotive subject but unfortunately like most people I am not trained in stripping down and rebuilding the engine in my car! So let's look at this idea about deposits another way - burning hydrocarbons makes deposits, so would you not get your home gas boiler cleaned and serviced to keep it working efficiently? I have a 2009 Kia Rio 1.4L petrol on 60k miles, the engine is a simple DOHC 16v unit with a cast iron block. I chose this product because the datasheet indicated that it is x5 more 'concentrated' than the equivalent Redex, so this was essentially the same cost versus 'cleaning power'. During the past two years I have occasionally used Redex and I am certain it has improved the engine's response and the fuel consumption, but exactly how much I don't know. The only issue I have had with this product is with dosage, the bottle label contradicts the products US website, so I used 50% bottle in 9 gallon (imp) tank. After one tankful I would say it has helped low-end performance (up to 3k rpm) but did not improve fuel economy for same *driving style*, I think the economy gain is cancelled because you inadvertently continue to use more throttle for the same rate and so use more fuel, so maybe I'll try to accelerate with less throttle and see if I get an improvement. I think next time I will try either Techron or Seafoam. At the end of the day I see this as a one-off preventative measure on a car that I put £150pcm worth of petrol into, it may be that my 10-mile commute and occasional 'Italian tune-up' are ideal in reducing the build-up of deposits.

Does the job

I don't have a problem with my car but I have just bought it used and although it has full service history, I am unaware of what fuel(s) were being used in it. I personally only use named petrol stations, not supermarket fuel, and I didn't think it would be a bad thing to draw a line in the sand. I only do about 4000 miles a year which is what the bottle recommends, so I'll probably do one every 6 months due to the low mileage. I will update this review at some point to let you know if I notice any change etc.

Brillant

Very good

Cumple con su función original

To keep your fuel system clean and engine running smooth, I strongly recommend this especially for GDI engines to remove carbon deposits on pistons and fuel injectors.

La mia vecchia Punto seconda serie aveva cominciato a dare il segnale di problema al motore (spia gialla accesa nel cruscotto) senza dare apparentemente altri difetti. ho letto che poteva essere un problema alla sonda lambda e che cambiarla costava un tantinello caro. Ho acquistato questo detergente e aggiunto mezza bottiglia ad un Pieno di benzina. Ora sono passati 2 mesi e la spia gialla on si è più accesa ma, non solo: la punto ha ripreso a fare 19,2 km con un litro di benzina (prima 17,5) e quindi alla fine il rodotto mi è venuto gratis.

Looks like a copy, not original and not like photo

Buon prodotto, comprato perché in base alla dicitura equivale allo stesso prodotto in vendita sul sito italiano, dove per 200 ml si spende più o meno la stessa cifra. Questo da 400 ml, provato in 2 pieni consecutivi. Ho notato miglioramenti in accelerazione prima e seconda marcia, la macchina non strappa più. Miglioramenti anche nell'erogazione ad alte marce. Completamente soddisfatto, a questa cifra lo ricomprerò sicuramente (pagato circa 13 euro).