I have a 1987 dodge ram d150 with the 318 and in the last 2 weeks it has got a little hot and the coolant in the overflow tank has been boiling and actually seemed to put cracks in the overflow tanks. There is no leak around the water pump or anywhere else. What could the problem be??
Thanks

 

Bad head gasket or cracked heads!!! The excess pressure in the system that would cause your expansion tank to crack is from the high cylinder pressure. You may also have a crack in your block.