I have the exact one SouthArk linked, and found it very useful in diagnosing a failing power steering pump. I think it was $1.99 on sale at one of the parking lot tent sales at HF.
Try to pinpoint a general area where the noise is coming from. Also, how many miles on your HFCs? I've heard HFCs rattling when the insides start to deteriorate, but that's not terribly common.