Sydney

I too have exactly the same problem. This has started at around 40,000 miles and comes out with a high pitched squeal after it has warmed up. I am at a loss to know what it is. It certainly sounds like under the bonnet or the front tyres as you say. I sprayed a lubricant around the belt that drives the alternator which seems to stop it for a short time and I am wondering if this belt has hardened over a period of time and needs replacing. Any comments to help this would be appreciated.