Over the last few week, I have noticed a squeeling noise coming from the engine of my Astra SXi (H series) when I'm slowing down, or the engine is ideling.
It only starts after I've been driving for at least 20 minutes when the engine has warmed up. And if you turn the ignition off whilst its making the noise, it continues for for a few seconds after the engine has stopped.
I had the drive belt changed a few weeks ago, but it hasn't sorted the problem.
It sounds like air under pressure being squeezed out from somewhere.
Any suggestion would be helpful, and yes I've tried WD40 on the new belt.