Rinding noise in the front left wheel

Sometimes the heat shiled that sits behind the brake rotor will get bent and scrape the rotor. It will scrape intermitantly as changes in suspension geometry and suspension loading will push it closer by a millimetr or so.
Check the clearance between the rotor and the shiled. Pay specail attention to the area where it goes between the lower ball joint and the rotor as this is an area where it commonly gets bent.
It can get frustrating to get it straight because bending it in one place will casue it to flex in others. Just pull it away the best you can and play with it till it stops rubbing.