“It is known to be a powerful fuel system cleaner with one of the highest levels of PEA detergent. Without doing any specific testing it would be impossible to comment on how effectively the product is working inside of the fuel system and combustion chambers, and I haven't felt any noticeable change in performance yet (still early days) but that's not what I bought it for.
If you are looking for a high quality, high PEA containing fuel system cleaner, then I would highly recommend this product as it is known to be good quality, and is the best price I found when I looked.
I believe these things take time to work, and seeing as I still have some of the full tank with cleaner left, it is probably quite early to be asking for a review. Time will tell.”
“Tried a few cleaners but Red Line SI-1 stands out. Engine idled smoother and throttle response improved after one tank. Not a miracle fix, but great for older or high-mileage engines. Slight dip in MPG during cleaning, then back to normal. Pricey, but worth it for a proper deep clean every 20–30k miles.”
“I was having a misfire on my Audi S3 on engine start up from cold. Having used this product previously & finding it made a great difference to the engines running & performance i thought to give it another try as it was 4000 miles since. After putting it in an empty tank & going on a 80 mile trip the misfire has completely cleared & the Engine is back to normal. Would definately recomend the product as a cheap cure for Engine Fuel / injector Cleaner before going down the garage route.”
“The idling has improved, next I will check if my mpg has improved, I suspect it will. Whatever chemicals are in this cleaner seem to be cleaning up the injectors and my lambda sensor. The overall engine tone has improved to like it was from the factory.”
“I have been having problems with my Audi S3 having a slight misfire on cylinder 4. The next step was new injectors. I read a few reviews on Red Line S1-1 Fuel System Cleaner & purchased a bottle from Opie Oils. Delivery was very quick & as I was doing a 270 mile journey , put a full bottle in an empty tank & filled up. Got to say the Car is running so much better not sure if it's cleared the misfire but feels like it. Worth a go for £20. Possibly saved me £2500 .”
