Ben, have you sorted out your noise problem yet? I have a similar noise coming from my car, I found that it was coming from a "check valve" which is on the right hand side of the engine bay next to the bulk head. I will be posting a photo of the part on the website once I have worked out how to do it. The original check valve was broken and I assumed that replacing it would be all that was necessary. However, after changing the part it started to make a noise around 3-4K rpm, Sounds similar to your symptoms. I don't know exactly what this part does but hopefully some of the other members will
