Help a Newbie out please

[Stinger357]

When drving I hear a rattling sound like cardboard being hit by a fan. It is not coming from the engine If I allpy gas or not it still occurs. For about 20 seconds then it goes away. Any thing I should check for I know there are tons things under the car which could cause this.

 

[imp]

When drving I hear a rattling sound like cardboard being hit by a fan. It is not coming from the engine If I allpy gas or not it still occurs. For about 20 seconds then it goes away. Any thing I should check for I know there are tons things under the car which could cause this.

Check everything underhood which normally is in motion. Grasp fan blade, see if water pump shaft has any "play", moves side-to side. If yes, is pump leaking coolant yet? Could fan blade tips be hitting fan shroud to produce the noise?

Maybe noise originating from belt idler pulleys. Just my thoughts. imp