Both flow meters I have are quiet. Of course I burned one out when I wired it backwards after sleeving, and a replacement part is on it's way to fix it. 
But yeah, some people report them as being noisy at first then getting better over time.
What is noisy sometime is my MCP35x pump. At first it was very quiet. After tilting it sideways to secure a temp sensor to the heat sink it got noisy for some reason, but seems to have quietened back down somewhat days later.

But yeah, some people report them as being noisy at first then getting better over time.
What is noisy sometime is my MCP35x pump. At first it was very quiet. After tilting it sideways to secure a temp sensor to the heat sink it got noisy for some reason, but seems to have quietened back down somewhat days later.




















