Wont getting a lower temp thermostat reduce the temp of the water in the block becuase of the fact that it will open at a lower temp to allow colder water/antifreeze to enter the block.
No. Like the guy said it will only open the thermostat sooner and delay the time it takes for the engine to reach operating temperature. If the engine runs with coolant temps around 220 it will still continue to do so, but the temps will just creep up slower because the thermostat opened sooner. I suggest finding the problem (ie faulty cap most likely) instead of trying to bandaid the problem. The car did not boil coolant when you bought it and you should not need to run coolant additives or lower temp thermostats to stop the problem.
