High pitched noise in engine bay - VQ 3.8

[VQdude]

Hi all I have a strange issue with my VQ s2 Statesman V6. There's a very high pitched noise in the engine bay with ignition off, key out. Possibly around the alternator but hard to tell.

Started the other day, came out to a very flat battery. Had to put a basic 1.5A charger on it to get the voltage up enough so the smart charger would work, left that for the rest of the day. Came to disconnect the charger, heard this steady high pitched noise. Only stopped when I disconnected the battery.

Car started fine, steady 14 volts other battery, then it just stalled. Restarted and ran fine and no more noise.. Battery stayed charged during the week, moved it around the shed a few times, no more strange noise. Then today, took it for a 10 minute spin around the block, came back and voltage still good. Stopped the engine and within 10 seconds this noise started again, with engine off and key out.

I'm reluctant to take it any distance in case something really shits itself. Anyone had anything similar?

 

[BlackVXGTS]

The only time I had something similar, was when I had some kind of an electrical problem (on a VS), and the starter motor was running, without engaging the flywheel/flexplate.

 

[Immortality]

Pull the big cable off the back of the alternator and insulate it, then put the battery cables back on and see if the noise is gone.

 

[VQdude]

Pull the big cable off the back of the alternator and insulate it, then put the battery cables back on and see if the noise is gone.

Thanks for the tip, I'll give it a go.

 

[Fu Manchu]

 

[Immortality]

Awhhh.

 

[MikeC]

View attachment 264446

Time for an exhaust decat?