I used it in heating diesel (red) for the radiator, which had been in the tank for over 15 years from the previous owners of the house. I poured 2 bottles into 230lt and mixed it to combine.
Before I used it, adjusting the burner was very difficult. For it to work, I had to set the fuel pressure and air quite high, outside the manufacturer's limits based on the nozzle. When the weather got cold at night, it would stall and wouldn't ignite at all...
As soon as I used it, it improved dramatically.
Now ignition starts even when cold and with normal fuel pressure and air settings.

It saved me the trouble of emptying the tank, the mess, and the money I saved by not throwing away 230 liters of diesel.

I always use such cleaners for my vehicles, once every 5 to 10 thousand kilometers. I usually do it after a service or a trip where I refueled at gas stations I don't know. After 150,000 kilometers when I went for injector cleaning, they found them to be barely dirty and the first question they asked me was if I use such cleaners. They confirmed to me that these cleaners work, and I was right to use them. If there are failures in the injectors, it will "hurt" my wallet. I should note here that in a 2000 VW group car, I PREVENTIVELY changed the fuel pump at 210,000 kilometers. The mechanic was "stunned" when I told him I still had the factory pump. As for this specific product, it works very well and there is a difference after using it, both in fuel consumption and performance. Recommended! P.S. I keep the 5th star for the Liqui Moly injection cleaner

I used it on a Renault Clio mk3 1.2 tce, which seemed clogged (had some hesitation and a slight tremor at idle) and it improved.

Classic gasoline additive along with STP that you can find everywhere, helps in removing water, and "cleaning" the entire fuel system. In an old and worn-out vehicle, it did the job from the first moment, stopping some hesitations at low speeds, and increasing the idle. It's great for regular maintenance.