Fan that runs after shutting off car squealing

Hello to all, new to forum. We just bought a one owner 2006 Prius with 75 k on the odometer. The original owner provided us with all service records and the car has given no trouble at all. We have been having some weather in the teens and 20's the last couple of days. When we shut the car off there is a fan that comes on. It is squiling only when under 30 degrees or so. Sounds as if it's under the hood drivers side. Could someone tell me were it is located and what it is for? Thanks in advance.

 

Very short time less than a minute.

 

Yes we received all manuals, I will check it out again. not really annoying just making sure it was not something fixing to die on us. The car still has a warranty on it until 100 k she transferred to us.

 

That's what it sounded like until the temps dropped below 30 deg. And it doesn't squeal at each shut down its intermittent.

 

How could it get air in the loop? The pump is covered after paying a dignostic fee and $100.00 deductible.

 

Thanks, I will get with them Thursday.

 

Ok we were able to have it checked out at the dealer. Of course It has warmed up here so it's not sqealing anymore. The dealer has always serviced the car for the PO and they showed me were both the 3 way valve and the pump were both changed under warranty. They said nothing to worry about. I ask the PO and they said the car had made that noise anytime the temps drop below 35 deg since it was two weeks old. The dealer said we have another 75k warranty so if anything came up it is covered.