You guys know what else can cause boiling sounds and incorrect temp on the gauge.
Lack of coolant in the motor.
Once in a while I get one that reminds me that our systems can be a pain to get coolant into. Had one myself this weekend. Front was jacked up in the air, down etc etc it wouldn't take coolant. Pull your thermostat housing and thermostat. Fill through there if it's low. Give it a while then see if it hasn't burped a little air up and can be filled further. Do this with the cap off the radiator.
