Summer has finally hit the east coast. Driving down the road the engine temp guage sits about 90. Stop and go driving quickly sends the needle to about 110-120. It acts like it is low on coolant, but the level is correct in the expansion tank. It has the correct 50/50 mix. One other key that leads me to beleave I have air in the system is shortly after shutting the engine off I hear a boiling sound from the area around the battery. Sounds like it is coming from under the dash. It was my understanding that the system was self bleeding. Or is there a procedure to ensure all the air is out of the system.