Okay, the only way I can describe this sound is that it sounds exactly like when you try to get the last little drops of your coke out of the cup with a straw. Seems to be coming from the heater core, and it happens every 10 minutes or so, sometimes louder than others. I checked the coolant level and it looks fine, but I'm guessing there's an air pocket in the system. Am I on the right track?

Yeah you probably are, that sound usually indicates a low fluid level.

Thanks! Glad to see I was on the right track.

Considering the coolant is full in the radiator and the overflow has some in it, how would I go about removing this air bubble?

Park on a hill, start the car and squeeze the radiator hoses gently.

(In addition to Shawn's post - with the nose of the car pointed uphill)

Thanks guys!! I totally appreciate it. Gonna go give that a shot this afternoon.

 

Thanks again .

That is of course providing the t-stat is open so that the coolant from the engine circulates to the radiator right?