2010 ML350

Got a chirp coming from the serpentine belt. I can hear the chirp is coming from the top pulley. According to service records, the belt, tensioner and pulley were replaced at the dealer about 2 years ago. 25k miles or so ago?

As soon as I sprayed water on the belt, the noise stopped. Should I start with replacing the belt?

I did loosen the belt and spin all the pulleys- no noise at all.....

 

do you have fluid leak onto the rollers and belt?

 

The front is completely dry. The other thing I was thinking is pulley misalignment. Because when I took the belt off and put it back on, no chirp for a few weeks.

I'll start with the belt and see what happens. $25 and a 5 minute fix.