the temp gauge goes crazy for awhile it jumps up without the engine getting hot without any heat blowing out then goes down as fast as it went up then you get heat after that. just replaced thermostat, seem to be putting alot of antifreeze in, at least once a week. i do not have to put much n when i do.
Did you by any chance put an antifreeze leak stop product into the overflow resevoir? I had a smiliar issue with my car after using a stop leak product for an antifreeze leak. I added the product to the resevior instead of the rad and it blocked the inlet/outlet of the resevior not allowing antifreeze back into the rad.