Thread: Interesting noise

I had an interesting noise developed in the County today. Sounded like the alternator bearings were going - a loud droning noise.

It took a while to diagnose, but the eventual clue was that the dirty filter telltale on the aircleaner had changed to red. Then the penny dropped. The underbonnet insulkation has been disintegrating, and a bit of thin plastic sheet had been sucked against the grille on the end of the tube that leads to the aircleaner, where it was acting as a reed, vibrating in the draught.

John