I've seen at least 2 or 3 complaints from people that had to get theirs replaced multiple times to address it, some as many as 3 times. Certainly look around elsewhere, but it's not impossible that it could still be the culprit.

--Matt

 

I'm surprised nobody has mentioned your water pump going bad yet. :D

Yes, it is the water pump going out on you. my '10 MCS with 28000 did that when it was replaced.

 

I changed the pump and the sound is still there

 

Did you ever figure out what was causing the squeal/whistle ?

Cheers