Just got a brand new MX5 2022 automatic. Had it for a month and only 2000km, never driven hard.
Ever since day one, it makes a humming noise from 70-75 km/hr or from 75-70km/hr. (from middle centre of the car)
After couple hundred KM I put on, the same sound start happing in the 40km range and 20 km range.
I tried put on neutral and cruise at 75-70km/hr, the noise isn't there.

Anyone has any idea what it is?

 

=wezzyo;209459]Just got a brand new MX5 2022 automatic. Had it for a month and only 2000km, never driven hard.
Ever since day one, it makes a humming noise from 70-75 km/hr or from 75-70km/hr. (from middle centre of the car)
After couple hundred KM I put on, the same sound start happing in the 40km range and 20 km range.
I tried put on neutral and cruise at 75-70km/hr, the noise isn't there.

Anyone has any idea what it is?[/QUOTE]



I have similar problem
google says it could be bearing of wheels

 

I suggest taking to a shop have them place on rack and check for the sound location and type.

 

I don't think it's the wheel bearing. Because when I cruise on Neutral, the noise isn't there. If it's wheel bearing, it should make the same noise regardless of gears.

 

It has no indication from your information .... your quote "I tried put on neutral and cruise at 75-70km/hr, the noise isn't there." that suggests ruling out wheel bearing as a suspected first choice in the noise causing concern.

 

Differential. Some say they been driving with that noise for 20,000 miles and it's ok. They say it's Normal. Others say your differential is going. Pinion Gear. I have a 2008 NC 115K. It makes the whining sound only at 50-60 mph only on acceleration. Sound from middle of console. You can only hear it with the top up.The last owner changed Diff Gear Oil at 75K. It's time to do it again so I will change it but I know already it won't silence the noise.