Any idea what this noise might be?

[bananaberri]

It started today in very wet weather.

😩

 

 

[Avalon]

Tensioner/pulley/pump/alternator, should be easier to pinpoint in person. When was the timing belt last done and was the pump changed?

[gjnorthall]

You don’t mention if the noise improves as the engine warms up. The clue is damp or wet weather which causes auxiliary belts to squeal. If squirting  water on to the belt silences it, then a replacement belt is the solution. Once a belt starts to squeal - it’s surface becomes hard and polished so a replacement is the only long term solution.

[+robster+]

sounds like the belt is too tight and psteer pump bearing is squealing