I bought it, but I didn’t use it, because its use is not simple. It’s not just an additive that you pour into the gasoline tank. You have to remove the air filter, place the product inside a sprayer, have the engine running at specific RPMs, and spray the product into the air intake. Since it seems that my car’s entire exhaust system needs replacing, I didn’t go through the application process because it wouldn’t have made sense. So I’m keeping it as a backup for the future.

Considering that Liqui Moly products are quite effective, I’m giving it 3 stars because of the incomplete usage instructions at the time of purchase (if I had known the application process from the start, I might not have bought it).

In my case, it did a very good job. Apart from the fact that I haven't gotten a P0420 error again, the car has much better response.

Guys, I used it three times, and at the MOT they asked me if I had changed the catalytic converter. That's all I'm saying.

Unfortunately, I was not able to evaluate it. I tried to follow the procedure described by the site and the product at a car workshop to be sure. As soon as the technician removed the air hose that goes into the engine (Suzuki SX4), the engine would stop running.!!!

after two or three uses the car settled, the catalytic converter warning light did not come on again, I am satisfied

Meriva B A14NET, error P0420. Two packages with a pre-pressure pump at the inlet after the MAF once the engine has warmed up. Then, with half a tank, one package of the company's other maintenance product. It emitted a cloud of white-grey smoke from the back and now the engine breathes. Improved torque from low revs. I recommend it, it does what it promises!

Guys, buy it with your eyes closed, I got 4 and the first one did exactly the job I wanted.

Update: it didn't last long, I put another one in the intake and the car felt like it came back to life, so I probably have a problem with the catalyst. In any case, if you have done a lot of kilometers, it doesn't do much. It's more for prevention and a temporary solution, either to pass the MOT or every 5,000-10,000 kilometers as a precaution to keep the catalyst alive

I had a fault message for the catalyst. In my case, it didn't help at all... Probably due to bad fuel, we had damage to the coils, catalyst sensor 1&2, and the catalyst...

Attention, this specific product must be sprayed on the air filter. It has a procedure; you don't pour it into the reservoir. Now, whether it works, I don't know

I put 6 bottles in the butterfly of an Opel Astra G CC from 2000 a day before the inspection, and the guy there told me what a clean catalyst it has for its year

Used on Mondeo.mk4 2009. With error p0420 for the catalyst. It was giving me an error at 30 to 40 km. The first time, although it showed something, the error appeared again.

In the 3rd bottle, I noticed a significant difference in acceleration and consumption. So far, it's at 100+ km and hasn't shown an error. I hope it continues!!!

Hello..
In a 2005 Lancia Musa with Lovato LPG and 333,000 km, I got a p0420 error. At first, I cleared the error from the diagnostic tool, but after a few kilometers, it reappeared. I bought this product, applied it, and I have driven about 800 km without the error showing up again. It probably did the job... I might buy it again as a preventive measure to keep the system clean when I have time.

(For those who don't know how to use it. I took an old spray bottle, e.g., from Azax, emptied the liquid inside, and started spraying it directly into the engine's air intake. That is, at the throttle. First, I had started the car to warm it up, and at a steady RPM of about 3000, I began to spray it until it was finished.)

I didn't see any difference in myself without meaning that it doesn't work of course it always depends on the problem

I tried it with a pump on an Astra that was stalling and it didn't make any difference, nor did it emit anything from the exhaust. After a few days, I added the catalytic system clean to the fuel tank (even though it is considered a maintenance product) and now the car runs smoothly.

I bought it for my own Ford Focus and a friend's Ford Fiesta as the check engine light was on with error P0420. If you follow the instructions correctly, watching the company's relevant video on YouTube, it does a good job. Of course, if you see what the catalyst emits in an open space, you will understand.

You can't know what's going on inside, but you can notice a small difference in sound and how the engine works. Always use it with a sprayer! Read the instructions for use!

I used 2 packages, the car immediately unclogged and the consumption also decreased. 4 days later, everything is fine. It really did the job! If anything changes, I will come back.

It was used in a Toyota Yaris with 240,000 km, in combination with the "Liqui Moly Pro-line Carburetor & Throttle Valve Cleaner Spray" because it triggered a check P0420. Read how it is used (with a pressure sprayer), also watch the official company videos on YouTube. It did an excellent job (reducing hesitation and "breathing" the engine), but if the problems persist, visit a trusted mechanic. All these additives are good and useful, but not a cure-all for all car issues that arise.

I put it in a Passat 1.8 20V (atmospheric 125 horsepower), the car unclogged and it feels like it gained more horsepower, becoming more responsive and powerful! I drive it a lot in the city and it accelerates well.
Be careful with the correct application in order to see results and avoid damage (this is my personal opinion, I do not sign any contract). Rev the engine to 3,000 RPM, let the car warm up first, and then spray it with a pump, like the ones used for cleaning air conditioners (2 bar or more), onto the throttle in the form of a mist (pay great attention to the MAF and sensors just before the intake, otherwise damage may occur). If nothing happens after a few sprays, gradually increase the RPM up to a maximum of 3,700-4,000, but not for more than 3 minutes continuously, and the car will unclog. Then take a 15-20 kilometer drive on an open road and it's ready.
Pay attention to nosy neighbors because it will emit a lot of smoke and make noise.

A week after I installed it, the check engine light came on and after a few days, I changed the lambda sensor, then the catalytic converter.

I had a problem with the acceleration of my car. After much research, I discovered that it was the catalytic converter. After applying it, the car unclogged and fuel consumption was reduced.