When I first start my vehicle in the morning, it makes a sound like a coffee percolator (like a chirping sound).  What could be the cause of this? 

My first guess would be air in the cooling system. Subarus can be hard to burp out at times

def. check the radiator level - safely, when the engine is cool. actually look in the rad - don't trust the overflow bottle.

 

not sure from how you are describing the sound - could this be a slipping accessory belt?

 

or, does it really sound like a fluid?

 

maybe open the hood and have someone else start the car and listen. If it's louder inside the car, could be something with the coolant, a/c or fuel tank. If it's louder under the hood, maybe a slipping belt or.....?

 

 

also, next morning before starting, remove the gas cap. note any pressure in there, start the car.

Edited September 24, 201510 yr by 1 Lucky Texan