Purchased a new Cultus AGS, and from the first day, there is a hissing noise from the front left side at more than 80 kmh with a slightly heavy foot (2500-3000rpm). With light foot the noise comes at a higher speed like 90+, and stops when I stop pressing the accelerator. Other than that there is no other abnormal noise, no vibration or shaking and everything else including engine noise and mileage are normal like they should be in a Cultus.
I called the showroom it was delivered from and they answered that they will look at it when I bring it for the first inspection. At first inspection, I mentioned the issue to the mechanic, and took a drive. He acknowledged that its abnormal, and then another senior mechanic drove the car, and also acknowledged that its not normal. Then they kept on looking at the front wheel. They raised the car up and asked me to drive, I took it up to 160kmh, kept steady at 85-90 with similar rpm as on the road for like 10 minutes, but there was no noise. They couldn't figure it out and told that everything in the front wheels is as it should be, and the fact that the noise wasn't present when the car was raised rules out any engine related issue. They said that the noise could be the hair on new tyres hitting the shock from inside (I don't believe this explanation) and said that they have ruled out everything else. And also told to get it looked at again if it doesn't go away by the 5000 km inspection.
Now please tell what the issue could be that they couldn't figure out, and they did spent quite a lot of time with my car, and multiple people looked at it. Has anyone else experienced something similar?
About the noise, to me it sounds like air hitting something at high speed at the front-left of the vehicle, similar to air escaping from a balloon, and can be heard at 80+ kmh with rpm > 2500. It is constant and doesn't get louder at higher speeds, and goes away as soon as I release the accelerator. Its also not loud or abnormal enough for me to stop the car immediately. There is no vibration, the steering remains straight, gears shift normally too, everything feels right at the driver's seat except the noise.
The mechanic described it as something rubbing in the front left wheel, like a bearing, but everything was fine when he checked. For me I cannot narrow it down to the wheel, I can feel a general direction that is front-left side of the car. And it disappeared when the car was running lifted up in the air.
I know a good Japanese car mechanic who looks after cars of my colleagues, but I am not taking it to him due to warranty.