Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
Hi my name is***** you describe the noise? Is it metallic or a loud vibration?
While the engine is running open the hood and inspect the belt tensioner. Is it excessively vibrating back and forth? You can confirm it is the tensioner by removing the serpentine belt and running the engine for 30 to 40 seconds. Note - do not run the vehicle for extended time without the serpentine belt.
Other causes could be a bent water pump shaft or failed bearing, bent or cracked brackets, or bent fan clutch shaft. These should be visibly damaged so there are no tests.
I will be here when you respond with more information and the results of the test above.
The water pump bearings can be checked by wiggling the cooling fan, if play is felt the bearings are worn and may be making noise.