That is certainly the belt. It needs replaced before it breaks or damages something under there such as wiring.
Here are directions for replacement. There are a couple different designs, but these directions will indicate both. The pics attached correlate with the directions.
2005 BMW X3 3.0i (E83) L6-3.0L (M54)
Replacing Alternator Drive Belt (M52/S52/M52TU/M54/M56)
Vehicle Engine, Cooling and Exhaust Engine Drive Belts, Mounts, Brackets and Accessories Drive Belt Service and Repair Removal and Replacement Replacing Alternator Drive Belt (M52/S52/M52TU/M54/M56)
REPLACING ALTERNATOR DRIVE BELT (M52/S52/M52TU/M54/M56)
11 28 010 - Replacing alternator drive belt (M52/S52/M52TU/M54/M56)
If the drive belt is to be subsequently reused:
Mark direction of travel and reinstall drive belt in same direction of travel.
Necessary preliminary tasks:
- Remove fan clutch with fan impeller
- Remove A/C compressor drive belt See: Drive Belt > Removal and Replacement > Replacing A/C Compressor Drive Belt (M52/S52/M52TU/M54/M56)
- E85/E60: Remove radiator cover
- E85/E60: Remove fan cowl
Remove cap from tensioning roller.
Relieve tension on belt drive.
Remove drive belt.
Drive belt must be replaced if fouled with hydraulic fluid.
Check drive belt for coolant and oil residues, replace if necessary.
Check that belt is correctly positioned on belt pulleys.
Version with auxiliary tensioning roller.
Locking device of auxiliary tensioning roller must snap into groove on alternator.
Version on E85.
Version on E60/E65.
Let me know if that helps. Also, make sure that the belt hasn't damaged anything which may be why you have a coolant leak.
Images (Click to enlarge)
Sunday, August 23rd, 2020 AT 6:05 PM