Overheating

[redset1001]

94 Tahoe overheated , blew head gaskets and cracked heads. 200,000. Decided to rebuild, les than 200 miles did same thing, no warning no pinging wham overheated blown head gaskets. Have 1500 in rebuild, don't want to screw this motor up. Also the temp sensor melted right out of plug. Same as first time, this happened suddenly, no warning. Could lower hose be collapsing, radiator plugged up, though I flushed radiator. Maybe have it dipped?? Hope I'm posting this correctly, New so just learning the ropes. Also the Drain plug for radiator is it located on drivers side at bottom? Any suggestions would be appreciated. Know gaskets are done haven't taken apart to check heads, going to wait a bit and see if anyone else has had this happen and what's causing it. Again, hope I got this post right???