Part Question
 

We're talking about a 98 ML320.
I don't know what this part is called, I guess it could be described as a circulator pump for the heater. It's located near the battery, attached to the wall in the engine compartment. Has I couple of hoses attached to it, one runs thru the firewall into the cabin.
The thing is squealing like an animal and it's driving me nuts.
It's easy to get to, looks like something I could do.
My question is: "What is it called?", " How much does the part cost?" and "What's a fair price for parts and labor?"
Thanks.
Mike