strange overheating problem
 

OK guys,here it goes,93 ford explorer 4.0 4dr 4wd. When I bought it the temp gague didn't move,no problem,changed the thermostat but now when it warms up at an idle the temp needle will spike up half way,then go back down,after a few more minuetts it'll spike back up,and go back down. I noticed when it spikes up the top radiator hose starts to suck shut. Could this be a bad head gasket or worse yet a cracked head?! Any insight on this would be great!

RE: strange overheating problem
 

Check the radiator cap, may not be venting pressure fully from cooling system, could alos be poor circulation through other cooling components like radiator heater core etc.....