i have air in my coolant system and am unsure as how to get it out. The gauge will go up and down up and down.. all randomly too. it seems when i first start it and drive.. at one point it will go all the way up to hot then drop right down and from then on while driving it it might go up 3.4 of the way but not lal the way up anymore. i recently put in a titan motorsports 1.2mm metal head gasket and arp studs and etc.. i only had the head milled though. lately ive been hearing its so bad to not have the block milled. but at the time of doing it i heard alot that it didnt need to be milled because the block is cast iron and is very hard to warp. people are saying my hg might be blown. i just put it in about 600 miles ago. any ideas on this or how to get the air out of my system?