I have a mk5 Asrta 1.7 cdti sri 57 plate and when driving up hill in third or 4th gear from 20 mph to 30 mph I can here a squealing/rattling noise when my drivers window is open. The noise lasts for about 3 to 4 seconds and does not appear when I drive on the flat or down hill.
Could any one tell me what it might be