hello

After replacing two waterpumps i noticed  some things:

1) an original waterpump from Volvo: makes a whining noice while in use.
Ran 2000km. It did it from the beginning, one month ago

2) an NOT original waterpump does the same immediately after the
install. and is 2 weeks old.

Is this normal? We filled it up with normal water, cause the systems
have to be flushed one more time.
Can normal water cause these noises? Are the pumps broken? Are it the
belts (not orginal volvo)?
The belts seem not to loose and not to tight.

For both pumps: back to thes store and change while under waranty?

Or doesn't do this noise any harm?

greets and thanks,

lex