Benjamin Witte

Hi, I have a 2002 Trailblazer and a couple of days ago it started making this weird gurgling noise when I turn it on, that seems to come and go but mainly when it's sitting idle. Last night it starting to give off an odor that smells like burnt coolant that also comes and goes, I can smell it coming through the vent and the under the hood after I park. The engine isn't overheating or anything, but obviously something is wrong. Nothing seems to be leaking anywhere, although if I take the radiator cap off and let the car run the coolant will spill out, don't know if that's normal or not. What could this potentially be?