So i literally just assembled a fresh rebuild bottom end and cleaned and tested head both have minimal work done per fsp rule set. All new gaskets , water pump tb, the whole deal. finally have it back in the car for the 1st start up and it runs good at idle for a bit until it gets to around 175-180 degrees then it startes bubbling like crazy in the burp funnel attached to the top of the radiator. it happened last night and the thermostat hadnt opened yet, so instead of trying to trouble shoot last night i left it sit and topped off the burp funnel and let it sit overnight. fast forward to today fired the car up and messed with idle a bit and closed loop running due to the obd2 sensor not working. all the while keeping and eye on the cooling system no issues so far. about 20 minutes in the thermostat opens " good deal" return to passenger side of car to laptop to monitor coolant temp and next thing i know smell coolant look up ect is 206 and coolant is violently being spewed fromt eh burp funnel... turn off the engine and within a minute the burp funnel is empty. so do i have a air pocket somewhere or what could it be. all coolant lines are correct, there is heat in the heater core.im at a loss ive been rounds like this before but it was on 150k motors that had questionable previous maintanence. any help would be great im going to get another thermostat tomorrow and try that maybe thermo stat is no opening completely.