I hope you are all sitting down. The answer, none of the above. 5,5 months Just over £2k spent 7 Technicians inc 3 master techs with combined 110 years of experience. Every single f**ker telling me it's normal, it's how they sound. They are loud engines. Yeah, sure. This was only fuelling my ridiculous perseverance. This was my genuine and last attempt at this, today, before part-exing the car. The solution was inspired by my friends story. Story, which is beyond ridiculous and impossible and I'm not asking you to believe his story. Not that long ago he was sorting a timing chain on his S3 using only genuine parts. And before you say, oh, for sure he did something wrong. He didn't. What he doesn't know it's not worth knowing. The actual number of attempts it's ridiculous so all I will say is that it was more than 2. Eventually, a good friend of ours dropped of an aftermarket parts to him and yeah, you guessed it, or not, car was fixed. Between my last post and today, I also preformed another smoke test, intercooler bypass, Racingline Diverter valve with double the amount of seals and more VCDS diagnostics. How I approached this last attempt is this. For every problem you will have a list of items to test. All got ticked. Then a number of extra items was added to the list. All got ticked. Back to square one and this is where I got "inspired" by my friends timing chain issue. I replaced the PCV valve, again. Car fixed !!! Now, I need you to stop for a minute and just think what is happening here, because I don't believe for a second that both examples are isolated and when nothing makes sense, unfortunately, these days, you have to stop and question the quality of the genuine parts. Remember, back in February, Skoda dealer, replaced my original PCV with a genuine one. I ordered, same part number, same manufacturer (Kengst) genuine VAG PCV made in the same country to fix this. And no, no pinched seal or cracks or damage or whatever else may come to your mind. As I said, due to the "state" of the motor industry, when you tried everything and nothing makes sense, you've got to consider the fact that the genuine brand new part you just fitted was faulty before it has left the factory. >>>>>>> For ADMIN / MODERATOR consideration <<<<<<<<<< Please consider making this post sticky or make a new thread, I don't care. I genuinely don't wish anyone to go thru the bull**** I went thru especially when your car is under warranty and you don't want to void it, which is why I made sure to source identical PCV with 2025 date on eBay for 70quid, new. Same PN and everything. 5 months of stress, head scratching, nearly loosing my mind and a £2000 bill on top of that....all while having a Skoda Warranty and 110 years of experience between the master techs. Skoda dealer showed me another 2.0 TSI Kodiaq with identical issue, no fault codes, whistling and whooshing, which they deemed as normal, meaning the owner is simply unaware that he is driving a car with a fu*ked PCV. No faut codes, no abnormal data log = the dealer will stamp it as "normal behaviour". Thank you for all your suggestions and take care.