Change in vehicle noise at 3100 RPM??

The noise is so loud that it gives you a headache, inside the car. Hence why I need this fixed, as I will be unable to eventually resell the car as is.

Now that I can trigger it reliably Ill go back to square one and monitor the OBDII readings while its happening.

As for modifications, the first time I heard it was in the first week when I fitted a roof rack and took it out for the first freeway run. I initially thought it was some sort of harmonic wind effect on the roof rack. Really heavy cross wind that day. I have a few other minor customisations but all installed after the first time I heard the sound.

Actually, you just gave me an idea. If I can get it happening in 4th gear reliably, then I should pull over somewhere safe, pop bonnet and rev the car at 3100RPM and see if that makes it return. If it does, then it will be so much easier to fault than asking the mechanic to ride in the engine bay at 100KPH.

It still sounds like the cooling fan to me. How do you know it's not the fan, have you heard the noise with the bonnet up and seen the fan stationary?

I have just read that the power steering on the Gen 4 uses an electric pump (unlike the Gen 3 which uses a belt driven pump), not sure if it is true and I would doubt that would run with the keys out, but may be worth a look?

Robin

Most electric power steering uses a motor around the column, hence no pump or fluid.  There are electro-hydraulic systems but they're a bit niche.  It used to be thought impossible to make a 12V PAS system but technology moved on and killed off the proposed move to 42V cars, for which electric PAS was one of the main drivers.

I just had a look under the bonnet and there are no fluid hoses going to the steering box, so it must be the usual "dry" electric PAS.  Doesn't give feedback like hydraulic PAS, but Jimny steering is not exactly the pinnacle of feel in any of its guises!