Yeah, Derek I got air bubbles in my coolant before. Like Ryan said, first check and see if it is blowing hot air. If not ... KEEP the heater on full blast (lets coolant in the heater core) and jack the front of your car up as high as you can or put it on ramps. Run it with the cap off and it'll force the bubbles out. I had to do this on my Neon everytime I did a flush or it would airlock bad. Haven't had to do that yet on my MX6 yet though.
'02 Ford Mustang- [Procharged @ 8psi][Flowmasters][5-speed][Limo Tint]