My 2005 325i started making a whining sound when I step on the gas. It goes away when I let off the gas and push the clutch in, or at lower speeds, when I just let off the gas. It's high-pitched, and definitely coming from under the hood. Any ideas?
Could be apulley or belt related? you could try to lubricate several tensioners? pulleys one at a time/
Belt Tensioner You didn't say how many miles are on the car, but I'd suggest checking out the belt tensioner.
Good Advice Thank you both for the advice. After checking the belts and pulleys, I concurred and went to Murray BMW here in Denver. I had to replace the adjusting pulley and the deflection pulley. Monaco (my 325i) is now running smoothly again. Thank you both again.