Mercruiser 6.2 chirping noise

[DS_G]

Group, I have a 2008 Merc 6.2 MPI Bravo 3 with 500 hours. We just had the engine out to replace a corroded Y pipe. We replaced the raw water pump, alternator and P/S pump. After about 8 hours, a chirping noise developed, apparently from the front of the engine. The serpentine belt is fine and the two idler pulleys were replaced without results. The circulation pump was replaced about one year ago and is not leaking. All the pulleys feel fine when the belt is off. Using a stethoscope does not help to localize the source. My mechanic is stumped! BTW ignore the pressure gauges! Different issue!

Suggestions appreciated!

 

[vroom ZOOM]

Group, I have a 2008 Merc 6.2 MPI Bravo 3 with 500 hours. We just had the engine out to replace a corroded Y pipe. We replaced the raw water pump, alternator and P/S pump. After about 8 hours, a chirping noise developed, apparently from the front of the engine. The serpentine belt is fine and the two idler pulleys were replaced without results. The circulation pump was replaced about one year ago and is not leaking. All the pulleys feel fine when the belt is off. Using a stethoscope does not help to localize the source. My mechanic is stumped! BTW ignore the pressure gauges! Different issue!

Suggestions appreciated!

Chirping still there when the engine is running with no belt? Is the engine alignment ok? If yes, then pull the oil filter and look for metal.

 

[crazy charlie]

Check the fluid level of power steering pump.Low will make a chirp-like sound. Charlie

 

[Faztbullet]

Make sure you have the correct rib belt . Had this on a new customers HB and alternator had been replace and pulley grooves was one shy

 

[DS_G]

Thanks to all. I checked all these without findings. Although the original belt was nearly new and not previously noisy, I changed out the belt and the chirping has resolved !!