So when i bought my 03 spi it came with green coolant on the resevoir. Now that I'm doing a head swap i read int he manual that it requires a gold coolant type. Should i swap coolant for the gold type or should i keep using the green antifreeze? I would like to drain the antifreeze on the engine block (by disconnecting lower hose), but I'm not sure if i should leave the block empty and add water when I'm finish through the reservoir. Can someone offer advise? thanks!