OPEL ASTRA G 1999 206,000 KM
Because sometimes when starting a cold engine, it would, let's say, emit a puff of smoke from the exhaust, then it would stop.
I decided to try it.
I have used it three times since March 2025 along with three oil changes from the same company, specifically the Liqui Moly Molygen New Generation Synthetic Car Oil 10W-40 4lt, over a period of 2500 to 3000 KM.
RESULTS ARE PLEASANT.
The engine was cleaned and no longer emits any smoke on cold start, it doesn't burn a gram of oil, this is confirmed together with my mechanic, the engine runs very smoothly. And specifically, in the exhaust, I no longer see any soot, it is clean without deposits.
Of course, the downside is the cost, meaning oil and additive together are about 70 euros, but it is worth it and it was worth spending that much money.
Guys, what you need to do, since we all use the car in the city, and I ADVISE YOU to take the car out often, twice a month, to cover some distance. And three times a year I use a valve cleaning additive from the same company. I think it is the most reliable company out there.
All the best

Less noise after eighty kilometers of use. The engine works more eagerly and more quietly. Buy it.