Before I changed the oil, I used this specific product. I didn't see any positive difference.
Afterwards, the car was burning oil and I had to add 2 liters.
In the next oil change that I did, it still didn't burn oil, which means that the product contains gasoline and it thins out the oil.
Logically, it kept the Carter and the old oils should be drained before putting in the new ones.
I will not use it again. I prefer to use quality oils and change them more frequently.

The product does an amazing job. It takes half an hour before you need to change the oil, you put it in with a warm engine and after half an hour of the engine running, you will see the mess it will remove during the oil change.
I didn't have time to take a photo of the engine's interior from the top oil cap to show you how clean it became.
Oil and filter change is implied. And the engine will calm down significantly.

I bought it with reservations. Nevertheless, it seems to have done the job. The engine runs much quieter after the oil change!

Update
I tried it on another car, but this time I used different oils than the ones I used on the other car, and it really does a great job! Both of them work very smoothly!
Highly recommended!