2007 chevy avalanche. Engine temp fluctuating and blowing cold air during idle?

Engine bounces around between 210 and 260. Never going to the tho. When idling it blows cold air, but blows warm when in motion.


That means there is an air pocket in the cooling system. Look for leaks. Take the radiator cap off and check the coolant level. Run the motor for 15 minutes with the radiator cap off and top up the coolant as the air purges out of the radiator neck.


does it have a thermostat or is it stuck open?