You may want to check your fan/clutch assembly. The sound I was getting when mine went bad, was also like a grinding noise from the engine. I am sorry, but I don't know a way to test it. I just replaced mine and the grinding sound went alway.

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2010 X6 50i
2005 X5 3.Oi, Many Options
2015 HONDA CR-V EX-L
1998 ACURA 2.5TL

MODs
- Driver's outside mirror light
- Voice Recognition Module
- Blaupunkt Entertainment System
with Digital TV