Hi,
Sounds like you had an 'air lock' in the block somewhere or are using a small amount of water if it was down. The air lock will definately cause overheating going down the road. I would suggest putting in a little prestone rad seal [ small round tube of sealer granuals] and change your cap to a 16 lb cap and fill the over flow bottle 1/2 way to make sure water is being sucked back into the engine when cooling and not air. the 16 lb cap will keep more pressure in the block and is not as easy to have air locks. Also will raise the point where water is pushed out into the overflow bottle, as more heavy duty use go up the more cap pressure you need.Race cars such as oval track cars would use a 21 lb cap. If your fan clutch is not working properly I would change it out !!!!! It may just be seizing at idle and when higher RPM's or load put on ,it may free wheel and have no air movement, THIS IS probably your MAIN trouble.
Good luck,
Perry.
